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Biomedical subjects

T Oki

Publications and source records attributed to T Oki.

At least 109 records · Page 6Linked to original sources
PubMed1997

Clinical application of pulsed Doppler tissue imaging for assessing abnormal left ventricular relaxation.

Conventional assessment of left ventricular (LV) relaxation by calculating the time constant of LV pressure decay during the isovolumic diastole requires an invasive approach. Conversely, noninvasive parameters obtained by measuring isovolumic relaxation time and transmitral flow velocity often give inaccurate information. Using LV pressure curve, pulsed Doppler echocardiography, and pulsed Doppler tissue imaging in 38 patients with heart disease and 12 control subjects, we calculated the time constant and recorded transmitral flow velocity and motion velocities at the endocardial portions of the ventricular septum and LV posterior wall. Compared with the controls, patients exhibited a prolonged time constant, a decreased peak early diastolic velocity of the LV posterior wall, and a prolonged time interval from the second heart sound to the peak of the early diastolic wave. The time constant correlated well with the isovolumic relaxation time and various parameters calculated from the transmitral flow velocity, except in patients with elevated LV end-diastolic pressure. In all subjects, the time constant correlated negatively with the peak early diastolic velocity of the posterior wall and positively with the time from the second heart sound to the peak of the early diastolic wave. Thus, early diastolic parameters derived from the motion velocity of the LV posterior wall by pulsed Doppler tissue imaging were closely related to the time constant. This technique may allow noninvasive evaluation of abnormal LV relaxation in patients with various heart diseases.

Blood Flow Velocity↗
PubMed1997

Evaluation of left atrial appendage function by measurement of changes in flow velocity patterns after electrical cardioversion in patients with isolated atrial fibrillation.

We investigated temporary changes in left atrial appendage (LAA) flow velocity patterns in patients undergoing electrical cardioversion for chronic isolated atrial fibrillation, and evaluated the role of active LAA contraction in directing blood flow to the left atrial main chamber and left ventricle. The study consisted of 26 patients with chronic isolated atrial fibrillation treated with electrical cardioversion and 20 normal controls in sinus rhythm. Using transthoracic and transesophageal Doppler echocardiography, we recorded transmitral, pulmonary venous, and LAA flow velocity patterns before, 24 hours, and 1 week after cardioversion in all subjects. In the 15 patients who underwent successful cardioversion, the maximal LAA area 24 hours after cardioversion was smaller than the area before cardioversion, whereas LAA ejection fraction during atrial systole and peak atrial systolic emptying velocity of the LAA flow were lower 24 hours after cardioversion than those in the control group. One week after cardioversion, maximal LAA area and LAA peak atrial systolic emptying velocity were restored to levels approximately equivalent to those in the control group, although LAA ejection fraction was lower than in the control group. Maximal LAA area and LAA peak atrial systolic emptying velocity correlated negatively and positively with LAA ejection fraction, respectively, 24 hours and 1 week after cardioversion. These results suggest that LAA and the left atrial main chamber show stunning 24 hours after cardioversion, and the atrial systolic emptying wave of LAA flow is generated by active LAA contraction.

Adult↗
PubMed1997

Transesophageal pulsed Doppler echocardiographic evaluation of left atrial systolic performance in hypertrophic cardiomyopathy: combined analysis of transmitral and pulmonary venous flow velocities.

BACKGROUND: Hypertrophic cardiomyopathy (HC) is characterized by impaired left ventricular (LV) diastolic function due to an increase in LV wall thickness. The severity of this disease varies depending on the localization and extent of the hypertrophied myocardium and the presence and extent of myocardial disarray or fibrosis. HYPOTHESIS: The purpose of this study was to examine the background of hemodynamic abnormalities between the left atrium and the left ventricle during atrial systole in patients with HC using pulsed Doppler echocardiography. METHODS: Hemodynamic abnormalities between the left atrium and left ventricle during atrial systole were evaluated in patients with HC using transmitral flow (TMF) and pulmonary venous flow (PVF) velocities obtained by transesophageal pulsed Doppler echocardiography. The study population included 50 patients with HC, including 39 with asymmetric septal hypertrophy and 11 with apical hypertrophy, and showing fractional shortening of the left ventricle > or = 30%. They were classified into three groups: (1) Group A (n = 11): the ratio of the late to early TMF velocity < 1, and peak atrial systolic PVF velocity (PVA) < 25 mm/s; (2) Group B (n = 13): their ratio < 1, and PVA > or = 25 mm/s; and (3) Group C (n = 26): their ratio > or = 1. The mean age of patients in Group A was lower than that in Groups B and C. RESULTS: Left atrial dimension in Group B was significantly greater than that in the other HC groups and the control group. Furthermore, left atrial volume changes during atrial systole in Group B were significantly smaller than those in the other HC groups and the control group. Peak atrial systolic PVF velocity in Group B was significantly higher than that in the control group and in Group C. The duration of the atrial systolic waves of the TMF and PVF in Group B was significantly shorter and longer, respectively, than that in Group A. Left ventricular end-diastolic pressure (LVEDP) decreased in descending order with Group B > Group C > Group A. In all patients there was a significant positive correlation between the LVEDP and peak atrial systolic PVF velocity or the difference in duration between the atrial systolic waves of PVF and TMF. Plots of these values shifted toward the left and inferiorly in Group A, and toward the right and superiorly in Group B. CONCLUSION: Peak velocity and duration of TMF and PVF during atrial systole by transesophageal pulsed Doppler echocardiography are useful indices of hemodynamic abnormalities between the left atrium and the left ventricle during atrial systole, particularly a forceful atrial contraction mismatched to the left atrial afterload and severity of LV diastolic dysfunction, in HC.

Adult↗
PubMed1997

Echocardiographic characteristics and causal mechanism of physiologic mitral regurgitation in young normal subjects.

BACKGROUND: It has become evident that mitral regurgitation (MR) is not uncommon in healthy subjects, and Doppler color flow mapping is a technique that imparts important information relevant to its detection. HYPOTHESIS: Using transthoracic echocardiography, this study evaluated the mechanism of physiologic MR in young normal subjects using transthoracic echocardiography. METHODS: The study population consisted of 48 young normal subjects (mean 21 +/- 5 years) with MR (physiologic MR group), 40 age-matched young normal subjects (mean 20 +/- 5 years) without MR (control group), 45 patients (mean 41 +/- 15 years) with mitral valve prolapse with MR (MVP group), and 27 patients (mean 59 +/- 13 years) with ruptured chordae tendineae (rupture group). RESULTS: Men were predominant in the rupture group, whereas there were no significant gender differences in the other three groups. Left ventricular end-diastolic dimension and left atrial systolic dimension were slightly smaller in the physiologic MR group than in the control group, but were significantly smaller than those in the MVP and rupture groups. The ratio of the maximum anteroposterior diameter to the maximum transverse diameter on chest radiography and the ratio of the short- to long-axis diameter of the left ventricular cavity at end diastole, determined from two-dimensional short-axis echocardiogram, were significantly lower in the physiologic MR group than in the other three groups. Mitral regurgitation occurred more frequently at the posteromedial commissural site in the physiologic MR and MVP groups, whereas there was no preference for location in the rupture group. Early systolic MR was often observed in the physiologic MR group, whereas pansystolic MR was common in the MVP and rupture groups. CONCLUSION: As a causal mechanism for physiologic MR detected in young normal subjects, "flattening" of the thorax during growth may cause morphologic abnormalities of the left atrial and ventricular cavities, resulting in spatial imbalance of the mitral complex and resulting in malcoaptation of the valve.

Adult↗
PubMed1997

Correlation of body fat distribution with grade of endometrial cancer.

To elucidate whether body fat distribution correlates with the grade of endometrial cancer, we studied 74 postmenopausal women with endometrial cancer (mean age 62.4 +/- 6.6 years, range 49-78 years). The subjects were divided into three groups as follows: well-differentiated adenocarcinoma (G1 group; N = 53), moderately differentiated adenocarcinoma (G2 group; N = 11), and poorly differentiated adenocarcinoma (G3 group; N = 10). Four body fat indices [total fat weight (g), body fat ratio (%), trunk fat weight (g), and weight ratio of trunk fat to leg fat (trunk/leg ratio)] were measured by dual-energy X-ray absorptiometry. Baseline characteristics and body fat indices in the three groups were compared. In all subjects, the correlations of these variables with the grade of adenocarcinoma were investigated using single and stepwise regression analyses. Total fat weight, body fat ratio, and trunk fat weight showed slight increases with the grade of differentiation. The trunk/leg ratio in G1 group was significantly higher than in G2 and G3 groups. The trunk/leg ratio was significantly correlated with the grade in stepwise regression analysis. Body fat distribution in women with endometrial cancer may correlate with the grade of the adenocarcinoma.

Absorptiometry, Photon↗
PubMed1997

Enhancement of human parainfluenza virus-induced cell fusion by pradimicin, a low molecular weight mannose-binding antibiotic.

Oligosaccharides, especially mannose residues, expressed on the cell surface, are thought to be important for virus-induced membrane fusion. We examined the effect of mannose-binding compounds, pradimicin derivative BMY-28,864 (PRM) and concanavalin A (Con A), on cell fusion of human parainfluenza type 2 virus (hPIV2)-infected HeLa cells. Syncytium formation of hPIV2-infected HeLa cells was suppressed in the presence of Con A. On the other hand, PRM enhanced cell fusion of hPIV2-infected HeLa cells. These effects were blocked by addition of mannose-rich mannan. However, PRM shows little effect on virus growth and the expression of viral glycoproteins on the cell surface in hPIV2-infected HeLa cells. Fluorescein-isothiocyanate-labeled pradimicin and Con A bound to both uninfected and hPIV2-infected mononuclear cells, indicating that these compounds have an affinity to several cellular component(s). In contrast to Con A, PRM had little affinity to the viral glycoproteins. It is inferred from these results that the enhancement of hPIV2-induced cell fusion is probably due to the interaction between PRM and cellular component(s).

Anthracyclines↗
PubMed1997

Predictors of bone mineral loss in patients with ovarian cancer treated with anticancer agents.

OBJECTIVE: To identify factors predicting bone mineral loss during anticancer chemotherapy. METHODS: Fifteen women (mean age 38.2 +/- 7.8 years; range 30-46 years) with ovarian cancer who had been treated with cisplatin-adriamycin-cyclophosphamide for six cycles every 4 weeks following surgical cytoreductin were studied. Bone mineral density (BMD) of the lumbar spine (L2-L4) was measured by dual-energy x-ray absorptiometry before and after chemotherapy. Fifteen age-matched women whose ovaries had been removed surgically for other reasons. served as controls. None of the patients had received hormonal treatment. The two groups were compared for percentage change of BMD (BMD%) over the same period. In the chemotherapy group, total fat mass, body fat ratio, total lean mass, percent lean, and ration of trunk fat to leg fat were measured by dual-energy x-ray absorptiometry. Lean loss during chemotherapy was also calculated. These variables were compared before and at the end of chemotherapy. Possible correlations of baseline variables with BMD% were determined in univariate and stepwise regression analysis. RESULTS: Mean ( +/- standard deviation) BMD decreased to 87.4 +/- 2.1% after six cycles of chemotherapy and 97.6 +/- 0.4% after 6 months in controls, but the greatest decrease was observed in the chemotherapy group (P < .001). Although baseline lean mass, baseline BMD, body weight, and lean loss during chemotherapy were correlated with BMD% in univariate analysis, baseline lean mass was still significant in stepwise regression analysis. CONCLUSION: Baseline lean mass predicts bone mineral lose with anticancer chemotherapy.

Adult↗
PubMed1997

The effect of body composition on bone density in pre- and postmenopausal women.

OBJECTIVES: To investigate the relative contribution of body composition (lean and fat) to bone mineral density (BMD), 196 premenopausal and 128 postmenopausal Japanese women were enrolled. METHODS: Total fat mass, total lean mass, lumbar BMD (L2-L4), and total body BMD were measured by dual-energy X-ray absorptiometry (DEXA, Hologic QDR 2000, MA. USA). Physical characteristics were also recorded for each subject. Correlation between BMD and variables were calculated for each of the two groups in single and stepwise regression analyses. RESULTS: Total lean mass was significantly higher in premenopausal women than postmenopausal women (P < 0.0001), while body weight, body mass index, and total fat mass were not different between the two groups. In stepwise regression analysis, total lean mass was the most powerful determinant of lumbar BMD and total body BMD in premenopausal women. In postmenopausal women, total fat mass was the most significant determinant of lumbar BMD, while total lean mass was the most significant determinant of total body BMD. CONCLUSIONS: These findings suggest that there is a difference between pre- and postmenopausal women in the relative contribution of lean and fat mass. Total lean mass is the most significant determinant of BMD in premenopausal women. On the other hand, total fat mass may have some advantages in maintaining BMD in postmenopausal women.

Adipose Tissue↗
PubMed1997

Possible association of body-fat distribution with preeclampsia.

OBJECTIVE: To investigate whether preeclampsia is associated with body-fat distribution. METHODS: Twenty-two patients with preeclampsia (mean age: 31.9 +/- 6.0 years) and 126 controls without preeclampsia (mean age: 30.9 +/- 5.2 years) were enrolled in this study. We compared baseline characteristics and 4 body-fat indices measured by DEXA on Day 5 postpartum. The possible correlation between the variables and the development of preeclampsia was evaluated by multivariate analysis. RESULTS: The body-fat ratio, the upper-half body-fat amount, upper-half-body body-fat amount ratio, and upper-/lower-half-body body-fat amounts ratio on Day 5 postpartum were significantly higher in the preeclampsia group. However, the upper-/lower-half-body body-fat amount ratio was best correlated with preeclampsia among variables in multivariate analysis. CONCLUSION: Upper-body-fat distribution might be associated with the development of preeclampsia.

Absorptiometry, Photon↗
PubMed1997

Cross sectional echocardiographic demonstration of the mechanisms of abnormal interventricular septal motion in congenital total absence of the left pericardium.

OBJECTIVE: To investigate the influence of the absence of the pericardium on the left ventricular wall, particularly on interventricular septal motion, using M mode and cross sectional short axis echocardiography in patients with congenital total absence of the left pericardium. METHODS: 21 patients with, congenital total absence of the left pericardium were divided into three groups according to the interventricular septal motion; systolic type (n = 6) with paradoxical motion during systole, diastolic type (n = 11) with abnormal posterior motion during mid to late diastole, and mixed type (n = 4) with paradoxical motion during systole and abnormal posterior motion during diastole. RESULTS: On cross sectional short axis echocardiograms of the left ventricle, in the diastolic type the degree of angular displacement of the papillary muscles during end diastole to end systole showed excessive anticlockwise rotation about the long axis of the left ventricle without marked anteroposterior displacement. In the systolic type, there was shift of the left ventricle towards the anteromedial portion in systole and towards the posterolateral portion in diastole without significant rotation. There was a significantly positive correlation between the degree of angular displacement and the amplitude of diastolic interventricular septal motion during mid to late diastole in all patients. CONCLUSIONS: There was abnormal interventricular septal motion during systole and diastole in patients with total absence of the left pericardium. Abnormal systolic motion was induced by anteroposterior displacement of the left ventricle, and abnormal diastolic motion by left ventricular rotation about the long axis of the heart during the cardiac cycle. Analysis using cross sectional echocardiography was useful for elucidating the mechanisms of abnormal interventricular septal motion.

Adult↗
PubMed1997

Unusual left ventricular wall motion and a loud added sound during the isovolumic relaxation period in a patient with hypertensive heart disease.

A 69 year old woman with hypertensive heart disease had a loud added sound which coincided with a sudden interruption of the early diastolic motion of the left ventricular posterior wall, as visualised by M mode echocardiography, and came just before early diastolic transmitral flow, as measured by a pulsed Doppler echocardiogram. Early diastolic motion velocity from the base to the middle of the posterior wall, assessed by pulsed Doppler tissue imaging, was markedly high and sharp, and its peak coincided with the sound. A notch, similar to that in the posterior wall motion, occurred in the left ventricular pressure curve during early diastole. No intraventricular flow signal was detected during the isovolumic relaxation period, as measured by pulsed and colour Doppler imaging. The added sound was probably produced by impact between the dilated heart, with a relaxation abnormality, and the extracardiac structures during the isovolumic relaxation period.

Aged↗
PubMed1997

Pradimicin, a mannose-binding antibiotic, induced carbohydrate-mediated apoptosis in U937 cells.

Pradimicin (PRM), a mannose-binding antifungal antibiotic, recognizes a D-mannoside in the presence of calcium. We demonstrated that BMY-28864, a semi-synthetic analog of PRM, induced apoptosis in U937 cells which had been incubated with 1-deoxymannojirimycin (DMJ). Characteristic morphological changes such as formation of apoptotic bodies and DNA fragmentation were observed in apoptotic cells.

1-Deoxynojirimycin↗
PubMed1997

Cloning and nucleotide sequence of the putative polyketide synthase genes for pradimicin biosynthesis from Actinomadura hibisca.

We cloned the putative polyketide synthase genes (pms genes) for pradimicin A biosynthesis from Actinomadura hibisca using an oligonucleotide probe designed on the basis of conserved amino acid sequences of other polyketide synthases (PKSs). By DNA sequencing of an 8.2-kb SacI fragment that hybridized with the oligonucleotide probe, 11 open reading frames (ORFs) were found. All of the ORFs except for ORF10 were predicted to be translated in the same direction. Each of the deduced ORFs has significant sequence similarity to the protein responsible for polyketide biosynthesis or spore pigmentation. In particular, ORF1, ORF2, and ORF3 were 50-70% identical with genes coding for PKSs for actinorhodin biosynthesis. Specific DNA regions similar in sequence to pms genes were found with genomic Southern hybridization in all of the pradimicin producers examined, but were not found in pradimicin nonproducers, suggesting that the genes cloned in this study encode polyketide synthase for pradimicin biosynthesis.

Actinomycetales↗
PubMed1997

Concealed left ventricular hypertrophy and diastolic dysfunction in hypertrophic cardiomyopathy in the presence of acute left ventricular volume overload. A case report.

We report a patient in whom hypertrophic cardiomyopathy, with both left ventricular hypertrophy and diastolic dysfunction, was masked by acute severe aortic regurgitation and marked left ventricular dilation. Upon admission, 1) two-dimensional echocardiogram of the left ventricle revealed a dynamic and flail vegetation on the aortic right coronary cusp and marked left ventricular dilation, 2) a massive aortic regurgitant signal was recorded by color Doppler flow imaging, and 3) transmitral flow velocity by pulsed Doppler echocardiogram revealed a pseudonormalization. However, symmetric hypertrophy of the left ventricular wall, a decrease in early diastolic wave and a compensatory increase in atrial systolic wave of the transmitral flow velocity appeared after successful aortic valve replacement.

Aortic Valve↗
PubMed1997

Transesophageal echocardiographic prediction of initially successful electrical cardioversion of isolated atrial fibrillation. Effects of left atrial appendage function.

Left atrial appendage (LAA) flow velocities prior to electrical cardioversion were recorded using transesophageal pulsed Doppler echocardiography to predict initially successful cardioversion of isolated atrial fibrillation (AF). Patients with AF were placed into either a success group (19 patients) in which sinus rhythm was maintained for at least 2 days or a failure group (12 patients). The duration of AF was shorter in the success group. The maximum left atrial diameter was the same for the two groups. The maximum LAA area was smaller in the success group. The maximum forward and backward LAA velocities were greater in the success group, as were the mean forward and backward LAA velocities. In the patients with mean LAA flow velocities greater than 19 cm/sec, the success of cardioversion could be predicted with high sensitivity (80%) and specificity (88%). We conclude that the duration of AF, the maximum LAA area, and LAA flow velocities prior to cardioversion predict the initial recovery of sinus rhythm for isolated AF.

Adult↗
PubMed1997

Tricuspid inflow and regurgitant flow dynamics after mitral valve replacement: differences relating to surgical repair of the tricuspid valve.

BACKGROUND AND AIMS OF THE STUDY: Changes in tricuspid inflow and regurgitant flow dynamics were evaluated in patients with functional tricuspid regurgitation (TR) who underwent mitral valve replacement (MVR) with and without tricuspid annuloplasty (TAP). METHODS: In a group of 30 patients, all with atrial fibrillation, 15 underwent TAP performed according to the modified De Vega technique; the remaining 15 did not undergo TAP. Patients were studied before and serially after surgery, using pulsed and color Doppler echocardiography. The mean follow up was 4.7 years in the TAP group and 5.1 years in the non-TAP group. RESULTS: In the TAP group, immediately after surgery, the area of the TR jet decreased markedly, and the deceleration time of the tricuspid inflow velocity wave was significantly prolonged compared with that before surgery. By contrast, in the non-TAP group, both the area of the TR jet and deceleration time of tricuspid inflow velocity were virtually unchanged. The area of the TR jet remained small for a long period in the TAP group, but in non-TAP patients was increased in four cases over seven years, with two patients developing right-sided heart failure. Recent data showed the area of the TR jet to be significantly smaller, with maximum tricuspid inflow velocity significantly increased, and deceleration time of the tricuspid inflow velocity wave significantly prolonged in the TAP group compared with the non-TAP group. CONCLUSIONS: In patients with functional tricuspid regurgitation undergoing MVR, concomitant TAP may cause mild tricuspid stenosis, but produces sustained preventive effects against TR. Careful follow up is needed in patients who have not undergone TAP, as TR is not markedly decreased and may even be exacerbated. Aggressive TAP is recommended in patients showing dilatation of the tricuspid annulus, even if TR is mild.

Adult↗
PubMed1997

The 'sail sound' and tricuspid regurgitation in Ebstein's anomaly: the value of echocardiography in evaluating their mechanisms.

We describe a patient with Ebstein's anomaly in whom Doppler echocardiography was used to clarify the mechanism responsible for 'sail sound' and tricuspid regurgitation associated with this condition. Phonocardiography revealed an additional early systolic heart sound, consisting of a first low-amplitude component (T1) and a second high-amplitude component (T2, 'sail sound'). In simultaneous recordings of the tricuspid valve motion using M mode echocardiography and phonocardiography, the closing of the tricuspid valve occurred with T1 which originated at the tip of the tricuspid leaflets, while T2 originated from the body of the tricuspid leaflets. Using color Doppler imaging, the tricuspid regurgitant signal was detected during pansystole, indicating a blue signal during the phase corresponding to T1 and a mosaic signal during the phase corresponding to T2 at end-systole. Thus, 'sail sound' in patients with Ebstein's anomaly is not simply a closing sound of the tricuspid valve, but a complex closing sound which includes a sudden stopping sound after the anterior and/or other tricuspid leaflets balloon out at systole.

Diagnosis, Differential↗