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T Tabata

Publications and source records attributed to T Tabata.

At least 127 records · Page 7Linked to original sources
PubMed1997

[Effect of thoracoscopic procedure versus standard posterolateral/muscle-sparing thoracotomy on pulmonary lung function].

To understand the effects of thoracoscopic approach to thoracotomy on lung function, we investigated the changes in lung function after thoracoscopic operation (n = 7) and compared them to those after standard posterolateral (n = 5) or muscle-sparing thoracotomy (n = 6). In 18 patients with benign lung tumor in which surgical treatment resected in partial resection of the lung tissue, we measured TLC, VC, RV, FEV1.0, FEV1.0%, Peak Flow and DLco preoperatively and at 2, 4 weeks postoperatively. In the standard posterolateral or muscle-sparing thoracotomy groups, FVC, TLC, FEV1.0 and Peak Flow decreased to about 80% of preoperative value at 2 weeks. At 4 weeks after operation, these values showed to increase some what, but did not reach to the preoperative value. Whereas, the thoracoscopic procedure group, did not show the decrease in lung function through the time course. There was not significant different between standard posterolateral and muscle-sparing thoracotomy. We conclude that thoracoscopic approach is an useful technique to thoracotomy because of its minimizing after thoracotomy effect of lung function loss.

Adult↗
PubMed1997

[Increase in pulmonary vascular permeability caused by increased expression of Mac-1 on the surface of polymorphonuclear leukocytes].

We studied the expression of adhesion molecules on the surface of human polymorphonuclear leukocytes (PMNs). The effects of mechanical stimulation were measured with a flow cytometer and pulmonary vascular injury due to accumulation of PMNs in the lungs was assessed by a gravimetric method. The accumulation of PMNs in the lungs was studied by measuring the amount of myeloperoxidase. PMNs were stimulated by gentle agitation in a glass container for 10 s. Mac-1 (CD11b/CD18) was upregulated on the surface of PMNs that were mechanically stimulated. When unstimulated PMNs were exposed to isolated rat lungs, the filtration coefficient did not change from that under baseline conditions. However, when mechanically stimulated PMNs were exposed to isolated rat lungs, the filtration coefficient was about 5 times higher than that measured at baseline. When mechanically stimulated PMNs treated with anti-CD18 antibody were used, the increase in the filtration coefficient was completely blocked. The assay of myeloperoxidase revealed that PMNs stuck to isolated rat lungs only after stimulated PMNs were added. We conclude that when the adhesiveness of PMNs is increased by mechanical stimulation, these cells adhere to pulmonary vessels and increase pulmonary vascular permeability.

Animals↗
PubMed1997

[Prediction of postoperative pulmonary hemodynamics for the second lobectomy after the contralateral lobectomy].

We presented 7 cases who were performed the second lobectomy for the second lung cancer after the first successful lobectomy on the contralateral lung (3 cases for right upper lobectomy + left lower lobectomy and 4 cases for right upper lobectomy + left lower lobectomy). In 6 patients, the predicted postoperative FEV1 estimated by multiplying the preoperative FEV1 by the fraction of perfusion to the contralateral lung was less than 800 ml/m2BSA, which is our first cut-off for identifying lung resection candidates. Unilateral pulmonary arterial occlusion test (UPAO) revealed that total pulmonary vascular resistance (TPVRI) in 3 of those 6 patients was lower than 700 dyne.sec.cm-5/m2BSA, our second cut-off for lung resection. More precise postlobectomy pulmonary hemodynamics in another 3 of those 6 patients were then estimated by adapting selective pulmonary occlusion test (SPAO). Since TPVRI during SPAO was lower than the cut-off value, it was suggested that second lobectomy would be feasible with low incidence of post operative cardiopulmonary complication. There was no serious complications in all 7 cases during their postoperative course. We believe that more precise prediction of postoperative pulmonary hemodynamics by adapting UPAO and SPAO could be one of the tools to minimumize postoperative cardiopulmonary complications in those patients needed second lobectomy for the second lung cancer after the first successful lobectomy on the contralateral lung even though their impaired lung fung function.

Aged↗
PubMed1996

Hepatitis C biochemical remission and viral replication in haemodialysis patients.

The natural course of non-A, non-B (type C) hepatitis was studied in 62 haemodialysis patients. From the onset of the disease, serum alanine aminotransferase levels were monitored monthly for 9-218 mon (median 115). After fluctuation of aminotransferase levels for 1-206 mon (median 39), 57 (92%) patients showed normalization of these levels lasting until the end of the follow-up, which was for > 2 yr in 31 (50%) cases and for > 5 yr in 15 (24%) cases. At the end of follow-up, hepatitis C viraemia was assessed by reverse transcription-polymerase chain reaction (RT-PCR) and branched DNA (bDNA) assay. Viraemic levels were significantly lower in the 15 patients with normal aminotransferase for > 5 yr (median RT-PCR + ve/bDNA-ve, range RT-PCR-ve to 10(6.7) Eq/mL) than in the 47 cases with normal levels for < 5 yr (median 10(6.6), range RT-PCR + ve/bDNA-ve to 10(7.6) Eq/mL) (P < 0.01). Moreover, a significant inverse relation was observed between viraemic levels and the duration of aminotransferase normalization (r = -0.46, P < 0.01). These findings indicate that biochemical remission of hepatitis C may be frequent in haemodialysis patients and may be related to viral attenuation.

Adult↗
PubMed1996

Changes in left ventricular inflow and pulmonary venous flow velocities during preload alteration in dilated heart.

The aim of the present study was to assess the changes of left ventricular inflow (LVIF) and pulmonary venous flow (PVF) velocities during preload alteration in 30 patients with dilated heart (LV end-diastolic dimension > or = 6.0 cm) and impaired LV systolic function (% fractional shortening of the LV < or = 25%). We performed transesophageal pulsed Doppler echocardiography during lower body negative (LBNP, -40 mmHg) and positive pressure (LBPP, +40 mmHg) in 10 patients with dilated cardiomyopathy, in 20 with old myocardial infarction, and in 22 healthy controls. Eight of the patients showed a pseudonormalization (compliance failure) pattern, and 22 showed a decreased early diastolic wave and compensatorily increased atrial systolic wave (relaxation failure) pattern of LVIF in the control state. Mean pulmonary capillary wedge pressure (PCWP) was greater in the compliance failure group than in the relaxation failure group in the control state. LVIF in 6 of the 22 patients with the relaxation failure pattern changed to the compliance failure pattern during LBPP, and that in 3 of 8 patients in the compliance failure group changed to the relaxation failure pattern during LBNP. The 6 patients with a change from the relaxation failure to the compliance failure pattern showed significantly higher peak diastolic and atrial systolic PVFs during LBPP than in the control state, and significantly higher PCWPs in the control state than the 16 patients with no change in LVIF. These findings suggest that the compliance failure and relaxation failure patterns of LVIF are readily interchangeable in various hemodynamic conditions, and that pattern analysis of LVIF and PVF during preload alteration is useful for understanding the hemodynamic severity and for evaluating preload reduction therapy in the dilated heart.

Blood Flow Velocity↗
PubMed1996

Clinical significance of the apical late systolic ejection murmur: a new phonocardiographic sign indicating dynamic mid-left ventricular obstruction.

Systolic ejection murmurs of the left heart usually have their peak during early to mid-systole. Few reports have addressed ejection murmurs with their peak at late systole. We evaluated the clinical significance of an apical systolic ejection murmur with a peak intensity during late systole using Doppler and two-dimensional (2-D) echocardiography and phonocardiography. The apical late systolic ejection murmur was observed in 9 of 13 consecutive patients with mid-left ventricular obstruction. We investigated the ejection flow velocity and the timing of maximum velocity at the three different sites of the left ventricle, the left ventricular cavity shape, and the timing of the peak murmur intensity in these nine patients (late-murmur group). The same parameters were also examined in 8 consecutive patients with mid-systolic ejection murmurs (mid-murmur group), 10 with early systolic ejection murmurs (early-murmur group), and 7 controls without murmurs. Patients with aortic stenosis were excluded. The mid-ventricular ejection flow velocity was significantly higher in the late-murmur group than in the other three groups; that of the outflow tract was markedly higher in the mid-murmur group. The ejection flow velocity at the aortic orifice of patients in the early-murmur group was significantly high compared with that of the controls. The timing of the peak murmur intensity in each group correlated with that of the peak flow signal at the corresponding site with maximum velocity. In all patients in the late-murmur group, 2-D echocardiography revealed a systolic narrowing of the cavity at the mid-ventricle. Amyl nitrite inhalation induced a marked increase in the intensity of the murmur without evidence of appearing or increasing mitral regurgitation. It was concluded that the apical ejection murmur with a late systolic peak intensity is a new phonocardiographic sign indicative of dynamic, mid-left ventricular obstruction. This murmur should be differentiated from the mitral regurgitant murmur.

Adult↗
PubMed1996

Possible mechanisms of mitral regurgitation in dilated hearts: a study using transesophageal echocardiography.

HYPOTHESIS: This study was undertaken to clarify the mechanisms of mitral regurgitation (MR) in dilated hearts. METHODS: In all, 68 patients with dilated heart and MR, including 26 patients with dilated cardiomyopathy (DCM), 24 with prior anterior myocardial infarction (A-MI), and 18 with prior posteroinferior myocardial infarction (I-MI), as well as 25 normal subjects were examined by transesophageal two-dimensional and color Doppler echocardiography. RESULTS: The maximum area of the MR signal in the DCM group correlated positively with the anteroposterior diameter of the mitral annulus at late systole. Although the coaptation edge length of the anterior and posterior mitral leaflets appeared shorter in dilated hearts than in the hearts of controls, a significant difference did not exist. The length of the coaptation edge correlated negatively with the maximum area of the MR signal in all dilated hearts, and characteristic systolic displacement of the coaptation point of both mitral leaflets occurred. The MI groups demonstrated anterior and posterior displacement in the direction of the short axis of the left ventricle in the A-MI and I-MI groups, respectively. However, the DCM group demonstrated inferior displacement toward the long axis of the left ventricle; its magnitude correlated positively with the maximum area of the MR signal. CONCLUSION: A major cause of MR in dilated hearts is mitral malcoaptation due to displacement of the coaptation point of the mitral leaflets along the long or short axis of the left ventricle. This is caused by left ventricular enlargement and/or asynergy of the left ventricular wall, rather than by a decrease in mitral coaptation edge length due to mitral annular dilation.

Adult↗
PubMed1996

Omega-conotoxin-MVIID blocks an omega-conotoxin-GVIA-sensitive, high-threshold Ca2+ current in fish retinal ganglion cells.

Reduction of Ca2+ current amplitude by the Conus peptide omega-conotoxin-MVIID (omega-CTx-MVIID) was measured in voltage-clamped, goldfish retinal ganglion cells. Effects of depolarizing shifts in holding potential, and sequential applications of omega-CTx-MVIID, omega-CTx-GVIA, and BAY-K-8644, together with effects of Ni2+ and omega-Aga-IIIA, indicated that omega-CTx-MVIID may target Ca2+ channels differing from those termed T, L, N, P < Q and R.

Animals↗
PubMed1996

Changes in transmitral and pulmonary venous flow velocity patterns after cardioversion of atrial fibrillation.

To examine the recovery time of left atrial mechanical function after electrical cardioversion of atrial fibrillation, we recorded transmitral flow, pulmonary venous flow velocities, and interatrial septal motion during atrial systole within 24 hours (16 +/- 5 hours) and 10 days after cardioversion in 25 patients with atrial fibrillation, including 6 patients with hypertension, 4 with ischemic heart disease, 2 with alcoholic heart disease, 5 with dilated cardiomyopathy, and 8 with no evidence of underlying heart disease. With the exception of the five patients with dilated cardiomyopathy, the peak atrial systolic transmitral and pulmonary venous flow velocities, peak first systolic velocity of pulmonary venous flow, duration of both atrial systolic waves, and amplitude of the interatrial septal motion during atrial systole decreased markedly within 24 hours after cardioversion and increased 10 days after cardioversion. These results suggest that active atrial systolic and relaxant variables obtained from transmitral and pulmonary venous flow velocities may reflect left atrial mechanical function after cardioversion of atrial fibrillation.

Atrial Fibrillation↗
PubMed1996

Relationship between pulmonary capillary wedge V wave and transmitral and pulmonary venous flow velocity patterns in various heart diseases.

BACKGROUND: A large V wave in a pulmonary capillary wedge pressure (PCWP) tracing is characteristic of mitral regurgitation. However, the V wave is often increased in patients without or with no significant mitral regurgitation. METHODS AND RESULTS: The V wave was in the PCWP tracing investigated in 65 patients using transmitral flow (TMF) and pulmonary venous flow (PVF) velocity patterns obtained by transesophageal pulsed Doppler echocardiography. A large V wave was defined if the peak V wave minus the mean PCWP (V-mPCWP) was greater than 7 mmHg. Three study groups were formed: 15 patients with large V waves and significant mitral regurgitation, 15 patients with large V waves with no significant mitral regurgitation, and 35 patients with small V waves. The mPCWP and left ventricular end-diastolic pressure were greatest in the group with large V waves and no significant mitral regurgitation. Peak early diastolic TMF and PVF velocities were significantly greater in the two groups with large V waves. The peak second systolic PVF velocity was lowest in the group with large V waves and significant mitral regurgitation, followed by the group with large V waves and no significant mitral regurgitation. The V-mPCWP was positively correlated with the peak early diastolic TMF and PVF velocities and negatively correlated with the peak second systolic PVF velocities. Additionally, mitral regurgitation severity in patients with large V waves and significant mitral regurgitation was positively correlated with the peak early diastolic TMF and PVF velocities and negatively correlated with the peak second systolic PVF velocity. CONCLUSIONS: These results suggest that large V waves in PCWP tracings appear not only in severe mitral regurgitation, but also in any condition with markedly elevated left ventricular end-diastolic pressure. Combined analysis of the TMF and PVF velocity patterns is helpful in determining the etiology of these hemodynamic abnormalities.

Blood Flow Velocity↗
PubMed1996

Detour factors in water and plastic phantoms and their use for range and depth scaling in electron-beam dosimetry.

Average penetration depths and detour factors of 1-50 MeV electrons in water and plastic materials have been computed by means of analytical calculation, within the continuous-slowing-down approximation and including multiple scattering, and using the Monte Carlo codes ITS and PENELOPE. Results are compared to detour factors from alternative definitions previously proposed in the literature. Different procedures used in low-energy electron-beam dosimetry to convert ranges and depths measured in plastic phantoms into water-equivalent ranges and depths are analysed. A new simple and accurate scaling method, based on Monte Carlo-derived ratios of average electron penetration depths and thus incorporating the effect of multiple scattering, is presented. Data are given for most plastics used in electron-beam dosimetry together with a fit which extends the method to any other low-Z plastic material. A study of scaled depth-dose curves and mean energies as a function of depth for some plastics of common usage shows that the method improves the consistency and results of other scaling procedures in dosimetry with electron beams at therapeutic energies.

Electrons↗
PubMed1996

Relationship between the angiotensin converting enzyme gene polymorphism and the effects of enalapril on left ventricular hypertrophy and impaired diastolic filling in essential hypertension: M-mode and pulsed Doppler echocardiographic studies.

OBJECTIVE: To investigate the relationship between the angiotensin converting enzyme (ACE) gene polymorphism and the effects of the ACE inhibitor enalapril on left ventricular hypertrophy and impaired diastolic filling. DESIGN AND METHODS: Enalapril (5-10 mg/day) was administered for 12 months to 60 previously untreated patients with essential hypertension. M-mode and pulsed Doppler echocardiography were performed before and after treatment, and changes in various parameters after treatment with enalapril were examined. ACE gene polymorphism was examined by the polymerase chain reaction method and the patients were classified as having the 190 bp deletion homozygous (DD) genotype, the 490 bp insertion homozygous (II) genotype or the 490 bp insertion 190 bp deletion heterozygous (ID) genotype. RESULTS: The DD genotype was observed in 10 patients (17%), the ID genotype in 24 patients (40%) and the II genotype in 26 patients (43%). Plasma ACE activity before treatment with enalapril was significantly higher in seven patients with DD genotype than it was in 18 patients with ID genotype and in 14 patients with II genotype. In all of the 60 patients, the left ventricular mass index, the peak atrial systolic velocity:early diastolic velocity ratio and the deceleration time from the peak of the early diastolic wave to the baseline in transmitral flow velocity were decreased significantly after treatment with enalapril. The changes in left ventricular mass index and atrial systolic velocity:early diastolic velocity ratio after enalapril administration were significantly greater in the DD genotype group than they were in the other two genotype groups. CONCLUSION: Enalapril-induced regression of left ventricular hypertrophy and improvement in left ventricular impaired diastolic filling were significantly greater in the DD genotype group than they were in the ID and II genotype groups, suggesting that the circulating and tissue renin-angiotensin systems, particularly the former system, are most active in hypertensive patients with the DD genotype.

Adult↗
PubMed1996

Parturition in six renal allograft recipients.

Between 1983 and 1994, we studied renal function and neonatal conditions for eight pregnancies and births to six women who had received renal transplants in order to assess the effect of an allograft on pregnancy and its outcome. The gestation period was 34 to 39 weeks (mean 36 weeks and 4 days), and four pregnancies ended before term. All eight babies were delivered by cesarean section. Intrauterine growth retardation (IUGR) was found in both babies of one woman who had been treated with conventional (without cyclosporin) immunosuppression. The serum creatinine level did not change during gestation in any of the women but was elevated after delivery in four. Four mothers suffered from proteinuria (25-364 mg/dl) during gestation, but the proteinuria disappeared after delivery in all but one case. The one exception, persistent proteinuria of 100-200 mg/dl, was assumed to result from the recurrence of the original renal disease (lgA nephropathy). The reduction of creatinine clearance and hydronephrosis of one graft noted during gestation were later reversed. None of the eight babies (four females and four males) was congenitally malformed, and their Apar scores were 6 to 9 (median 8). They are now 3 months to 11 years old, and seven of them are healthy and show good growth. One of the two IUGR babies has not grown well; her weight and height are more than 1 SD below the mean for her age, and she is mentally retarded and suffers from muscle weakness. Compared with dialysis patients, female renal allograft recipient have a better quality of life because they can safely deliver a child if they observe the criteria for pregnancy established for renal allogaft recipients.

Child↗
PubMed1996

Transient and sustained depolarization of retinal ganglion cells by Ih.

1. Using whole cell patch-clamp methods, we have identified an inward cationic current activated by hyperpolarization (Ih) in somata of goldfish retinal ganglion cells. 2. Ih activated at test potentials between -70 and -105 mV, and did not appear to inactivate during prolonged hyperpolarizations under voltage clamp. During step hyperpolarizations from holding potentials between -70 and -40 mV, apparent activation was faster at more negative test potentials. On repolarization from -105 mV to holding potentials between -75 and -55 mV, Ih deactivated exponentially at rates showing no marked voltage dependence (tau = approximately 100 ms). 3. Ih tail currents reversed at membrane potentials consistent with a relative permeability to Na+ and K+ of roughly 0.5, when pipette and bath solutions both contained Na+ and K+. 4. Ih was readily blocked by extracellular Cs+ (3 mM), but was resistant to block by tetraethylammonium (30 mM), Ba2+ (1 mM), or Co2+ (2.4 mM). 5. Time-dependent voltage rectification developed during injection of hyperpolarizing current under current clamp. After current injection ceased, membrane potential depolarized beyond resting potential, often leading to anode-break-like spikes. Both voltage rectification and voltage overshoot were suppressed by extracellular Cs+. 6. Voltage-clamp measurements in the presence and absence of Cs+ were used to model membrane potential changes produced by exogenous current injections, by hyperpolarizing synaptic inputs, and by termination of both. Modeled responses resembled membrane potential changes measured under current clamp when terms for activation and deactivation of Ih were included. 7. The voltage rectification and anode-break-like spikes observed in isolated cells resemble those recorded during and after light-evoked hyperpolarizations of retinal ganglion cells in situ. Ih may transiently augment retinal ganglion cell excitability after termination of hyperpolarizing light stimuli, and thus promote encoding of stimulus timing.

Animals↗
PubMed1996

Assessment of left atrial pressure and volume changes during atrial systole with transesophageal pulsed Doppler echocardiography of transmitral and pulmonary venous flow velocities.

To determine whether transmitral and pulmonary venous flow velocity patterns can be used to evaluate left atrial pressure and volume changes during atrial systole, we performed transesophageal pulsed Doppler echocardiography and right heart catheterization in 85 patients (20 with hypertrophic cardiomyopathy, 20 with dilated cardiomyopathy, 30 with prior myocardial infarction, and 15 with mitral regurgitation), and 35 normal subjects. Pulsed Doppler variables from transmitral and pulmonary venous flow velocities during atrial systole were compared with mean pulmonary capillary wedge pressure (mean PCWP), pressure rise during atrial systole (PCWP-A), and left atrial volume change during atrial systole (delta LAV). The mean PCWP correlated significantly with the peak atrial systolic transmitral flow (r = -0.38, p < 0.05) and pulmonary venous flow (r = 0.40, p < 0.05) velocities in all patients. The PCWP-A correlated significantly with the peak atrial systolic transmitral flow (r = -0.39, p < 0.05) and pulmonary venous flow (r = 0.68, p < 0.0001) velocities in all patients. There was a particularly close correlation between the PCWP-A and the peak atrial systolic pulmonary venous flow velocities. The sum of the time-velocity integral of the atrial systolic transmitral and pulmonary venous flow velocities (TAI) correlated closely with the delta LAV (r = 0.70, p < 0.0001) in all patients. Thus, the peak atrial systolic pulmonary venous flow velocity correlated well with left atrial pressure changes during atrial systole. Furthermore, the sum of the time-velocity integral of the atrial systolic transmitral and pulmonary venous flow velocities correlated well with left atrial volume changes during atrial systole. Therefore, transesophageal echocardiographic measurements of atrial systolic transmitral and pulmonary venous flow velocities are reasonable indicators of left atrial pressure and volume changes during atrial systole.

Adult↗