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T Akasaka

Publications and source records attributed to T Akasaka.

At least 91 records · Page 5Linked to original sources
PubMed1998

Polymerase chain reaction amplification of long DNA targets: application to analysis of chromosomal translocations in human B-cell tumors (review).

Chromosomal translocations in human leukemias generate fusion transcripts containing messages from two genes involved in the translocation, and these have been the targets for reverse transcriptase-mediated polymerase chain reaction (PCR). In contrast, many of the translocations in B-cell tumors involve immunoglobulin gene (IG) loci, and coding regions of the oncogenes on partner chromosomes are not interrupted by the translocation. Therefore, targets for PCR amplification are single-copy oncogene/IG fusion sequences within the complex genomic DNA. We present here a novel strategy for detection of translocations in B-cell tumors on the basis of long-distance (LD-) PCR that is capable of amplifying up to 30 kb of DNA. LD-PCR is a general method using primer pairs designed for distinctive regions of IG and oncogenes involved in translocations, and amplifying long DNA fragments encompassing the oncogene/IG junction. LD-PCR is capable of detecting virtually all the important translocations in B-cell tumors, including t(8;14)(q24;q32), t(14;18)(q32;q21), t(3;14)(q27;q32) and its variants. We show here that LD-PCR can substitute for time-consuming Southern blot hybridization in the rapid detection of these translocations. Furthermore, as amplified fragments obtained by LD-PCR contained exons and flanking sequences of the oncogenes and IGs, restriction analysis and nucleotide sequencing of the products refined the characteristics of translocations.

Chromosome Mapping↗
PubMed1998

[Long-term results of mitral valve repair with artificial chordae tendineae].

The long-term results of mitral valve repair using artificial polytetrafluorethylene (PTFE) chordae were assessed in 61 consecutive patients with pure mitral regurgitation who underwent mitral valve repair with replacement of elongated or ruptured chordae tendineae between 1992 and 1996. There were 36 men and 25 women aged from 14 to 73 years (mean 52.1 +/- 13.8 years). The patients were followed up for between 1 to 73 months (mean 29.3 +/- 17.6 months). Fifty-five patients underwent mitral valve repair of the anterior leaflet and 6 repair of the posterior leaflet. There were two hospital and two late deaths. Actual survival rate at 5 years was 93.1%. Freedom from cardiac events at 5 years was 87.8%. Two patients required reoperation due to hemolysis. There were three occurrences of non-fatal thromboembolism. Although further investigation is necessary in a large population, expanded PTFE sutures are excellent for chordal replacement during mitral valve repair.

Adolescent↗
PubMed1998

[Serial changes in mitral regurgitation after mitral valve repair with artificial chordae tendineae: assessment by transesophageal echocardiography].

Serial changes in mitral regurgitation after anterior mitral valve repair were examined by transesophageal echocardiography (TEE) in 34 of 86 consecutive patients with pure mitral regurgitation who underwent anterior mitral valve repair from 1987 to 1996. The patients were divided into two groups: 15 patients undergoing mitral repair with polytetrafluoroethylene (PTFE; PTFE group) and 19 undergoing conventional mitral repair without PTFE (non-PTFE group). The PTFE group included 11 men and 4 women with a mean age of 52.1 years. They were followed for mean 22.8 +/- 12.0 months. The non-PTFE group included 12 men and 7 women with a mean age of 53.9 years. They were followed for mean 33.9 +/- 20.4 months. Mitral regurgitation jet areas were observed at the time of operation, 1 month after mitral valve repair, and in the late follow-up period. Regurgitation jet areas were 0.7 +/- 0.7, 1.1 +/- 0.9 and 2.5 +/- 2.1 cm2 in the PTFE group, and 1.1 +/- 1.3, 2.4 +/- 1.7, 4.7 +/- 2.9 cm2 in the non-PTFE group. The jet area was significantly smaller in the PTFE group than in the non-PTFE group at 1 month after operation and in the late follow-up period. Moderate to severe regurgitation was observed in two patients (13.3%) in the PTFE group, and eight patients (42.1%) in the non-PTFE group. Mitral valve repair with PTFE showed better results than conventional mitral valve repair without PTFE during the mean follow-up period of 23 months.

Adult↗
PubMed1998

[Automated cardiac output measurement by color Doppler echocardiography].

Recently, automated cardiac flow measurement (ACM) has been developed for measuring the volume flow rate of blood flow through the left ventricular outflow tract. Measurements of left ventricular cardiac output by the ACM method were compared with those by the thermal dilution method with a Swan-Ganz catheter in 27 patients (16 men and 11 women; aged 44 +/- 3 years) in whom clear two-dimensional and color Doppler images of the left ventricular outflow tract were obtained. The total time required for left ventricular stroke volume calculation by both ACM and pulsed Doppler methods was measured in 10 patients (six men and four women; aged 41 +/- 2 years). There was an excellent correlation in the measurements of cardiac output between the ACM and thermal dilution methods (y = 0.77x + 0.77, r = 0.84, SEE = 0.4 l/min). The total time required for left ventricular stroke volume calculation by the ACM method was significantly shorter than that by the pulsed Doppler method (92 +/- 10 vs 177 +/- 30 sec, p < 0.01). The ACM method is simple, quick, and accurate for the automated assessment of cardiac output.

Adult↗
PubMed1998

[Assessment of coronary flow reserve in patients with hypertrophic cardiomyopathy using transthoracic color Doppler echocardiography].

Abnormal coronary flow pattern and coronary vasodilator reserve have been identified in patients with hypertrophic cardiomyopathy (HCM) using invasive techniques. The characteristics of coronary flow velocity and coronary flow reserve were evaluated by noninvasive-recording of coronary flow velocity in the distal portion of the left anterior descending coronary artery in 7 patients with HCM and 7 normal subjects using transthoracic color Doppler echocardiography. Coronary flow velocity was measured at rest and during intravenous infusion of adenosine triphosphate (0.15 mg/kg/min). Diastolic peak velocity, diastolic mean velocity, the time from the beginning of diastole to peak velocity (TVP) and velocity half time from peak velocity was measured in each group. Coronary flow reserve was obtained as the ratio of hyperemic mean velocity to resting mean velocity. TVP was significantly prolonged in the patients with HCM compared with the normal subjects (159 +/- 38 vs 103 +/- 54 msec, p < 0.05). Velocity half time was significantly shorter in the patients with HCM compared with the normal subjects (304 +/- 138 vs 451 +/- 109 msec, p < 0.05). Although diastolic mean velocity during hyperemia was not different between the 2 groups (62 +/- 8 vs 70 +/- 19 cm/sec), diastolic mean velocity at rest was significantly higher in the patients with HCM than in the normal subjects (39 +/- 6 vs 26 +/- 7 cm/sec, p < 0.01). Therefore, coronary flow reserve was significantly lower in the patients with HCM than in the normal subjects (1.6 +/- 0.4 vs 2.7 +/- 0.4, p < 0.001). There was a good correlation between diastolic mean velocity and the ratio of interventricular septal to posterior left ventricular wall thickness (y = 0.024x + 0.46, r = 0.75). Transthoracic assessment of coronary flow velocity using color Doppler echocardiography reveals that coronary flow reserve is reduced in patients with HCM because of increased baseline resting diastolic mean velocity.

Cardiomyopathy, Hypertrophic↗
PubMed1998

[A newly designed parallel connecting tube makes feasible high speed blood transfusion with a transfusion pump].

Use of a transfusion pump (BP 101, Terumo, Tokyo) makes it feasible to obtain a stable and almost constant ejection volume at a flow rate of 99 ml.min-1, with no untoward effects of the intravenously placed needle and the microfilter located in the circuit. An air sensor ensures that the pump will cease operation immediately and automatically if an air bubble occurrs in the circuit. When a blood bag is conventionally connected to a connecting tube, at the maximum flow rate, one must set up a new blood bag within a few minutes, and in emergency situations with a shortage of hands, this would be unduly troublesome. When 5-7 blood bags (400 ml) is connected to 5-7 parallel connecting tubes, the pump will continuously eject blood approximately to 2000 ml at 99 ml.min-1, without replacing the blood bags.

Blood Transfusion↗
PubMed1997

Automated assessment of mitral regurgitant volume and regurgitant fraction by a newly developed digital color Doppler velocity profile integration method.

Recent development of the automated cardiac flow measurement (ACFM) method has provided automated measurement of stroke volume and cardiac output by spatial and temporal integration of digital Doppler velocity profile data. The purpose of this study was to evaluate the clinical usefulness of the ACFM method using digital color Doppler velocity profile integration in the assessment of mitral regurgitant volume and regurgitant fraction from measurements of both aortic outflow and mitral inflow volumes. We calculated both aortic outflow and mitral inflow volumes from the apical approach with the ACFM and pulsed Doppler (PD) methods in 20 patients with isolated mitral regurgitation. Mitral regurgitant volume and regurgitant fraction were calculated by the following equation: mitral regurgitant volume = (mitral inflow volume) - (aortic outflow volume), % regurgitant fraction = (mitral regurgitant volume)/(mitral inflow volume) x 100. Mitral regurgitant volume and regurgitant fraction were compared with that determined by the PD method. Mitral regurgitant volume measurement by the ACFM method showed a good correlation with that measured by the PD method (r = 0.90, y = 0.77x + 11.6, SEE = 9.0 ml); the mean differences between PD and ACFM measurements was -1.7 +/- 12.5 ml. Regurgitant fraction estimated by the ACFM method correlated well with that of the PD method (r = 0.92, y = 0.98x + 2.1, SEE = 8.8%). The mean difference for the measurement of regurgitant fraction between the PD and ACFM methods was 0.8 +/- 6.6%. Total time required for mitral regurgitant volume calculation in 1 cardiac cycle by the ACFM method was significantly shorter than that of the PD method (126 +/- 15 seconds vs 228 +/- 36 seconds, p <0.01). In conclusion, the newly developed ACFM method is simple, quick, and accurate in the automated assessment of mitral regurgitant volume and regurgitant fraction.

Adult↗
PubMed1997

Phasic coronary flow characteristics in patients with constrictive pericarditis: comparison with restrictive cardiomyopathy.

BACKGROUND: Phasic coronary flow characteristics have been reported in patients with aortic valve disease and hypertrophic cardiomyopathy. The purpose of this study was to assess the differences in coronary flow characteristics between patients with constrictive pericarditis and those with restrictive cardiomyopathy. METHODS AND RESULTS: The study populations consisted of 7 case patients with constrictive pericarditis, 8 with restrictive cardiomyopathy, and 11 control subjects with chest pain and normal coronary arteries. Five minutes after injection of 3 mg of isosorbide dinitrate, phasic coronary flow velocity patterns were analyzed in the proximal segment of the angiographically normal left anterior descending coronary artery at rest using a 0.014-in, 15-MHz Doppler guidewire. Coronary flow reserve was obtained from the ratio of adenosine-induced (0.14 mg x kg(-1) x min(-1) I.V.) hyperemic/baseline time-averaged peak velocity. Although in case patients with constrictive pericarditis and restrictive cardiomyopathy maximal hyperemic time-averaged peak velocity (21+/-8 and 31+/-17 versus 60+/-19 cm/s, respectively; P<.001) and coronary flow reserve (1.3+/-0.4 and 1.6+/-0.6 versus 3.6+/-0.4, respectively, P<.001) were significantly lower than in control subjects, there were no significant differences in these indexes between the two groups of case patients. Velocity half-time of diastolic flow velocity corrected by square root(RR), which indicates deceleration of diastolic flow, in the groups of case patients with constrictive pericarditis and restrictive cardiomyopathy was significantly less than that in control subjects (6.2+/-2.6 and 10.6+/-1.5 versus 16.9+/-2.7, respectively; P<.001); this was also significantly smaller in constrictive pericarditis than restrictive cardiomyopathy (P<.001). This index <9.5 could distinguish constrictive pericarditis from restrictive cardiomyopathy with a sensitivity of 86% and a specificity of 88%. Furthermore, time from the beginning of diastole to diastolic peak velocity corrected by square root(RR) indicating acceleration of diastolic flow velocity in constrictive pericarditis was significantly less than that in restrictive cardiomyopathy and control subjects (2.8+/-1.2 versus 4.8+/-0.8 and 4.4+/-0.6, respectively; P<.001). CONCLUSIONS: Although coronary flow reserve is limited in both constrictive pericarditis and restrictive cardiomyopathy because of restriction of hyperemic response, rapid acceleration and more rapid deceleration of diastolic flow velocity are more characteristic in constrictive pericarditis than in restrictive cardiomyopathy.

Adult↗
PubMed1997

Comparison of coronary flow reserve between focal and diffuse vasoconstriction induced by ergonovine in patients with vasospastic angina.

Decreased coronary flow reserve has been reported in patients with ergonovine-induced coronary vasoconstriction by the thermodilution method. To assess the difference of coronary flow reserve between patients with focal and diffuse vasospasm, after the vasospasm is discontinued by injection 3 mg of isosorbide dinitrate, phasic flow velocities of the diseased coronary artery were recorded at rest and during hyperemia (140 microg/kg/min of adenosine infusion intravenously) using a 0.014-inch, 15-MHz Doppler guidewire in 26 patients with ergonovine-induced coronary vasospasm (0.2-mg ergonovine injection intravenously), including 12 patients with focal (>90% stenosis), 14 patients with diffuse vasospasm (>50%), and 11 controls with normal coronary arteries without vasospasm. Although time-averaged peak velocity in cases with diffuse and focal vasospasm was not significantly different compared with that in controls at baseline (22 +/- 7, 18 +/- 5 vs 20 +/- 7 cm/s, respectively, NS), it was significantly lower in patients with diffuse vasospasm than in cases with focal vasospasm and in controls during hyperemia (43 +/- 13 vs 64 +/- 18, 61 +/- 19 cm/s, respectively, p <0.01). As a result, coronary flow reserve obtained from the ratio of hyperemic/baseline time-averaged peak velocity was significantly lower in patients with diffuse vasospasm than that in controls (1.9 +/- 0.4 vs 3.1 +/- 0.4, p <0.01), although it was not significantly different between the subjects with focal vasospasm and controls (3.5 +/- 0.7 vs 3.1 +/- 0.4, NS). Thus, coronary flow reserve is maintained normally in patients with focal vasospasm and limited in those with diffuse vasospasm. Microvascular impairment could exist further in cases with diffuse vasospasm, although similar endothelial dysfunction of the epicardial coronary artery is observed in focal and diffuse vasospasm.

Adult↗
PubMed1997

Expression of a neutrophil chemotactic protein LECT2 in human hepatocytes revealed by immunochemical studies using polyclonal and monoclonal antibodies to a recombinant LECT2.

A recombinant human neutrophil chemotactic protein LECT2 (rhLECT2) was purified as a 16-kDa protein from the culture fluids of stable transfectants derived from CHO cells (clone C1D8-1) and L929 cells (clone L2E4-1). The N-terminal amino acid sequence of the protein secreted by both clones were homologous to the previously described bovine LECT2. We produced polyclonal and monoclonal antibodies against rhLECT2 and investigated secretion of LECT2 protein in six human hepatoma cell lines, which express LECT2 mRNA, and in hepatocytes of normal human livers by a sandwich enzyme-linked immunosorbent assay and by immunostaining using the antibodies, respectively. We revealed that five of six hepatoma cell lines secreted LECT2 into culture fluids at concentrations of 30-135 ng/mg. We also demonstrated that the cytoplasm of human hepatocytes was diffusely stained, although periportal hepatocytes tended to be weakly and granularly stained by immunostaining. These results indicated that the novel protein was expressed in hepatocytes and suggested an important role of LECT2 in the cells in addition to the activation of neutrophils.

Animals↗
PubMed1997

Assessment of flail mitral leaflets by dynamic three-dimensional echocardiographic imaging.

To evaluate the usefulness of dynamic 3-dimensional images obtained by multiplane transesophageal echocardiography (TEE) in the diagnosis of the involved leaflets in patients with a flail mitral leaflet, 23 patients who underwent mitral valve repair were examined with multiplane TEE. In all patients, the involved lesions diagnosed by dynamic 3-dimensional images coincided with those confirmed at the time of operation; dynamic 3-dimensional images by multiplane transesophageal probe are useful in the evaluation of the involved sites in patients with a flail mitral leaflet.

Adult↗
PubMed1997

A recurring translocation, t(3;6)(q27;p21), in non-Hodgkin's lymphoma results in replacement of the 5' regulatory region of BCL6 with a novel H4 histone gene.

3q27 translocations affecting the BCL6 gene can involve not only immunoglobulin genes (IG) but also other as yet uncharacterized chromosomal loci as partners. Here, we describe cloning of the junctional area of a recurring translocation, t(3;6)(q27;p21), in non-Hodgkin's lymphoma of B-cell type and isolation of clones from 6p21; high resolution fluorescence in situ hybridization mapped the clones to sub-band 6p21.3. Nucleotide sequence analysis of a fragment from the junctional area of 6p21 revealed the presence of a novel H4 histone gene that was included in the histone gene cluster on this particular region, and the same fragment detected approximately 380-bp transcripts in hematological tumor cells. Breakpoints on 3q27 of two cases carrying t(3;6) were immediately 3' of the BCL6 exon 1, and the H4 histone gene was substituted for the 5' regulatory elements of BCL6. Because H4 gene expression is tightly coupled to DNA replication, this study suggested an immediate mechanism for deregulated expression of BCL6, leading to the development of non-Hodgkin's lymphoma.

Base Sequence↗
PubMed1997

False aneurysm of the popliteal artery treated successfully by surgery: report of two cases.

Blunt trauma to the popliteal artery may result in pseudoaneurysm formation. We herein report two patients who had a pseudoaneurysm of the popliteal arteries without any orthopedic injuries. One patient, who had been struck by an iron plate in the midthigh portion, demonstrated a pulsatile mass in this area 2 months later. The other patient had a pseudoaneurysm that was diagnosed by a histological examination; however, he could not remember having suffered any noticeable trauma.

Aged↗
PubMed1997

Planimetry and transthoracic two-dimensional echocardiography in noninvasive assessment of aortic valve area in patients with valvular aortic stenosis.

OBJECTIVES: The aim of this study was to evaluate the reliability of transthoracic two-dimensional echocardiography in measuring aortic valve area (AVA) by planimetry. BACKGROUND: Planimetry of AVA using two-dimensional transesophageal echocardiographic images has been reported to be a reliable method for measuring AVA in patients with aortic stenosis. Recent advances in resolution of two-dimensional echocardiography permit direct visualization of an aortic valve orifice from the transthoracic approach more easily than before. METHODS: Forty-two adult patients with valvular aortic stenosis were examined. A parasternal short-axis view of the aortic valve was obtained with transthoracic two-dimensional echocardiography. AVA was measured directly by planimetry of the inner leaflet edges at the time of maximal opening in early systole. AVA was also measured by planimetry using transesophageal echocardiography, by the continuity equation and by cardiac catheterization (Gorlin formula). RESULTS: In 32 (76%) of the 42 study patients, AVA could be detected by using the transthoracic planimetry method. There were good correlations between results of transthoracic two-dimensional echocardiographic planimetry and the continuity equation (y = 0.90x + 0.09, r = 0.90, p < 0.001, SEE = 0.09 cm2), transesophageal echocardiographic planimetry (y = 1.05x - 0.02, r = 0.98, p < 0.001, SEE = 0.04 cm2) and the Gorlin formula (y = 1.02x + 0.05, r = 0.89, p < 0.001, SEE = 0.10 cm2). CONCLUSIONS: Transthoracic two-dimensional echocardiography provides a feasible and reliable method in measuring AVA in patients with aortic stenosis.

Adult↗
PubMed1997

Retinopathy identifies marked restriction of coronary flow reserve in patients with diabetes mellitus.

OBJECTIVES: This study sought to assess the differences in coronary flow reserve in patients with and without diabetic retinopathy. BACKGROUND: Microvascular abnormalities throughout the body and impairment of coronary flow reserve have been described in patients with diabetes mellitus. However, the relation between diabetic retinopathy and coronary microvascular disease has not been investigated. METHODS: The study included 29 patients with diabetes mellitus (18 with and 11 without diabetic retinopathy) and 15 control patients with chest pain and normal coronary arteries. Diabetic retinopathy was nonproliferative in all 18 patients with this disorder (8 had background, 10 preproliferative retinopathy). Five minutes after injection of 3 mg of isosorbide dinitrate, phasic flow velocities were recorded in the proximal segment of the angiographically normal left anterior descending coronary artery at rest and during hyperemia (0.14 mg/kg body weight per min of adenosine infused intravenously) using a 0.014-in. 15-MHz Doppler guide wire. Coronary blood flow was calculated, and coronary flow reserve was obtained from the hyperemic/baseline flow ratio. RESULTS: Coronary blood flow was significantly lower during hyperemia ([mean +/- SD] 107 +/- 23 and 116 +/- 18 vs. 136 +/- 17 ml/min, respectively) and higher at baseline (58 +/- 16 and 45 +/- 12 vs. 37 +/- 10 ml/min, respectively) in diabetic patients with and without retinopathy than in control subjects (p < 0.05 for both diabetic groups). As a result, coronary flow reserve in both groups of diabetic patients was significantly lower than in control patients (1.9 +/- 0.4 and 2.8 +/- 0.3 vs. 3.3 +/- 0.4, respectively, p < 0.01 for both diabetic groups), and its reduction was greater in patients with than without retinopathy (p < 0.01). Furthermore, in patients with diabetic retinopathy, maximal hyperemic coronary flow (102 +/- 11 vs. 114 +/- 16 ml/min, p < 0.05) and flow reserve (1.6 +/- 0.2 vs. 2.3 +/- 0.2, p < 0.01) were significantly lower in those with preproliferative than background retinopathy. CONCLUSIONS: Coronary flow reserve is significantly restricted in patients with diabetes mellitus, and its reduction is more marked in those with diabetic retinopathy, especially in advanced retinopathy. Thus, diabetic retinopathy should identify marked restriction of coronary flow reserve in patients with diabetes mellitus.

Adult↗
PubMed1997

Echocardiographic estimation of left ventricular cavity area with a newly developed automated contour tracking method.

Development of an automated contour tracking method provides detection and tracking of the endocardial boundary using the energy minimization method without tracing a region of interest. The purpose of this study was to compare the automated contour tracking method and manually drawn methods for the measurement of left ventricular cavity areas and fractional area change. Apical four-chamber view was visualized and recorded for off-line analysis in 11 patients by means of two-dimensional echocardiography. The automated contour tracking method automatically traces the endocardial border from the recorded images and calculates left ventricular cavity areas (end-diastole and end-systole) and fractional area change. In the same images selected as end-diastole and end-systole in the automated contour tracking method, left ventricular endocardial border was manually traced to calculate left ventricular cavity areas and fractional area change. Both methods were compared by linear regression analysis for the measurement of cavity areas and fractional area change. Left ventricular areas measured by the automated contour tracking method showed an excellent correlation with those by the manual method (end-diastole: r = 0.99, y = 0.83x + 2.6; standard error of the estimate = 1.5 cm2; end-systole: r = 0.99, y = 0.96x -0.8, standard error of the estimate = 1.2 cm2). The mean differences between the automated contour tracking and manual methods were -3.1 +/- 5.1 cm2 and -1.6 +/- 2.4 cm2 at end-diastole and end-systole, respectively. Fractional area change determined by the automated contour tracking method correlated well with that by the manual method (r = 0.95, y = 1.17x -6.5, standard error of the estimate = 3.4%). The mean difference between the automated contour tracking and manual methods was -0.8% +/- 7.1%. In conclusion, a newly developed automated contour tracking method correlates highly with the manual method for the estimation of left ventricular cavity areas and fractional area change in high-quality images. This suggests that this new technique may be useful in the automated quantitation of left ventricular function in patients with high-quality images with no dropout and no intercavity artifact or structure.

Echocardiography↗
PubMed1997

Surgical treatment of traumatic rupture of the normal aortic valve.

Blunt trauma followed by aortic valvular insufficiency is a rare occurence. In one case, a male high-school student who had sustained a non-penetrative chest injury suffered from aortic regurgitation resulting from the rupture of the normal aortic valve. A sizable tear in the non-coronary cusp caused aortic insufficiency. The case was treated successfully by surgical replacement of the aortic valve with a No. 21 SJM prosthesis.

Adolescent↗