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Biomedical subjects

K Yokoi

Publications and source records attributed to K Yokoi.

At least 199 records · Page 11Linked to original sources
PubMed1984

[Simultaneous bilateral operations for bullous emphysema by median sternotomy].

Eighteen patients with bilateral bullae underwent simultaneous operations via median sternotomy. Each patient had giant bullae occupying at least one third of the each hemithorax and also had various degree of exertional dyspnea. All patients showed subjective as well as objective improvement and there was no mortality or morbidity. Late follow-up study for objective evaluation of this operative procedure clarified that the forced expiratory volume for one second (FEV1.0) and arterial oxygen tension (PaO2) were significantly improved after the operation, whereas the vital capacity and arterial carbon dioxide tension (PaCO2) showed no apparent changes. Serial study of cardiopulmonary hemodynamics during the bilateral thoracotomy was performed with Swan-Ganz catheter and hemodilution method. By abrupt decompression of the cyst, decreases in pulmonary arterial pressure, cardiac output, or systemic arterial pressure were noted during the bilateral thoracotomy. These hemodynamic changes were much more evident in the cases ventilated by single lumen tube than the cases operated upon using double lumen tube with separate ventilation. This operative procedure was applied on the cases with bilateral spontaneous pneumothorax and metastatic lung tumor. The clinical advantages of this bilateral operation via median sternotomy were discussed.

Adult↗
PubMed1984

[A study on the ruptured Valsalva sinus aneurysm using two-dimensional echocardiography].

We visualized the Valsalva sinus aneurysm ruptured into the right ventricle using two-dimensional echocardiography, and analyzed the blood flow by pulsed Doppler technic. Cross-sectional echocardiography was performed on 11 patients with right sinus aneurysm protruding into the right ventricle. The age of the examined subjects ranged from 17 to 40 years. Ten of the 11 revealed a ruptured aneurysm of the right sinus of Valsalva into the right ventricle. Nine of the 11 had ventricular septal defect and five were associated with aortic regurgitation. Pulmonic regurgitation was recognized in one case. The diagnosis was made by cardiac catheterization and angio-cardiography in all cases and was confirmed by cardiac surgery in nine patients. In this study, we employed an electronic (SSH-11A) or mechanical sector scanning system (SSL-51H) for cross-sectional echocardiography. In order to clearly visualize an aneurysm, the cross-section of the left ventricular long-axis was obtained from a slightly lower and more sagittal position than the standard method. In addition, the short axis cross-section of the aortic root was also examined. Furthermore, a pulsed Doppler technic was applied to three patients using a Doppler unit SDS-10A combined with SSH-11A. In all patients, an aneurysm of the right sinus of Valsalva was seen to protrude into the right ventricle by two-dimensional echocardiography. Furthermore, the ruptured orifice of the aneurysm was clearly visualized in ten cases. The shape of the aneurysm was tubular in ten cases and saccular in the remaining one. A continuous blood flow of wide band pattern was recorded in the right ventricle near the ruptured orifice in two of the examined three cases and a disturbed diastolic flow was noted in a saccular aneurysm. In conclusion, two-dimensional echocardiography is useful to visualize an aneurysm of the right sinus of Valsalva ruptured into the right ventricle and a pulsed Doppler technic is greatly contributed in detecting localized disturbed flow due to the ruptured aneurysm.

Adolescent↗
PubMed1984

[Abnormalities in the ventricular configuration and movement of the interventricular septum].

We discussed the left ventricular deformity in atrial septal defect (ASD) using two-dimensional echocardiography and elucidated the mechanism responsible for the production of mitral valve prolapse (MVP) associated with ASD. Two-dimensional echocardiography was performed for 78 cases with ASD, ranging in age from three to 64 years. The diagnosis was made by cardiac catheterization in all patients and was verified by surgical intervention in 66 cases. Two-dimensional images were obtained using an electronic sector scanning system of Toshiba (SSH-11A). The recording was made with 8 mm cinematography and an ordinary 35 mm camera. The major diameter/the minor diameter of the short-axis cross-section of the left ventricle was defined as the left ventricular distortion ratio (LVDR). The LVDR in early diastole was significantly larger than those in end-diastole and end-systole (p less than 0.001, n = 33). Furthermore, in end-diastole, the left ventricle showed a greater distortion ratio than that in end-systole (p less than 0.001, n = 33). The left ventricular short-axis area (LVSAA) corrected for the body surface area (BSA) was significantly greater both in early diastole and end-diastole than that in end-systole (p less than 0.001, n = 33). In early diastole, there was a poor correlation between the LVDR and the pulmonic to systemic flow ratio (Qp/Qs) (r = 0.44, p less than 0.05, n = 33). Similarly, the LVDR was poorly related with the right ventricular dimension (RVD) in early diastole (r = 0.43, p less than 0.05, n = 30).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

The development of a radioimmunoassay for formoterol.

The development of a radioimmunoassay (RIA) for the beta 2-stimulant formoterol is described. The sensitivity of the method is 0.1 ng/ml in plasma and urine, when a 1-ml sample is used. The cross-reactivity of the antiserum with formoterol glucuronide was 30%. Since formoterol is metabolized extensively to formoterol glucuronide in rats, dogs and humans, extraction with ethyl ether prior to the radioimmunoassay was carried out. Satisfactory agreement was obtained for levels of formoterol in plasma and urine when they were determined by RIA and gas chromatography-mass spectrometry. The concentration of formoterol was determined in dog plasma and human urine after oral administration of formoterol fumarate to dogs (61 mcg/kg) and humans (40 mcg).

Adrenergic beta-Agonists↗
PubMed1983

[2 Cases of cystic meningioma].

Although meningiomas are usually a solid and firm tumor, some are associated with diagnostically confusing large cysts. The authors experienced two cases of meningioma associated with large cyst (cystic meningioma). The first case was a 20-year-old female. She was admitted because of blurred vision. On admission she was slightly apathetic and showed bilateral papilledema. Computed tomography showed a large area of low density in both frontal regions. CT scan after intravenous contrast enhancement revealed an enhancing mural nodule attached to the falx. At operation, dark-green fluid in an amount of 160 ml from the left cyst and 50 ml from the right cyst was aspirated. The nodular tumor was found attached to the falx. The pathological examination revealed meningotheliomatous meningioma. Neoplastic meningothelial cells were found also in the cyst wall. The second case was a 21-year-old female. She was admitted because of weakness of the left lower extremity. Neurological examination revealed left hemiparesis. Deep tendon reflexes were hyperactive on the left side and there were positive left Babinski and Chaddock reflex. The computed tomography with contrast enhancement showed a large area of low density in the right parietal region with markedly enhancing mural nodule. At operation, 70 ml of xanthochromic fluid was aspirated. The tumor was well-defined, hard and attached to the dura. Histologically the tumor was a typical meningotheliomatous meningioma. The diagnostic value of computed tomography, the pathogenesis of cyst formation and the surgical treatment were discussed. The authors emphasized the important role of computed tomography in the diagnosis of cystic meningioma. Theories were reviewed for the pathogenesis of cyst formation. At operation, not only the mural nodule but also the cyst wall should be removed, because the neoplastic cells are presented in the cyst wall.

Adult↗
PubMed1982

Cross-sectional echocardiographic study on atrial septal defect: pre- and postoperative considerations.

The interatrial septum (IAS) has not been readily appreciated by M-mode echocardiography, but cross-sectional echocardiography has the capability of recording the shape and location of the IAS. Thirty-five patients with secundum atrial septal defect (ASD) were studied with cross-sectional echocardiography for detection of the ASD defect and demonstration of the IAS features following ASD closure. The ASD was shown as an echo dropout at the mid-portion of the septum in those patients examined in the present study in the horizontal cross-sections at the fourth intercostal space. The edge of the remaining IAS sharply demarcated and the defect was constantly demonstrated. In the postoperative patients, the IAS was recognized as a smooth series of echoes and the defect was no longer recognized. A notch echo was demonstrated in patients who underwent direct suture of the defect, and two notch echoes were recorded in patients who had a patch closure from a cardiac operation. The size of the defect at cardiac operation ranged from 1.5 to 5.0 cm with an average of 3.3 +/- 0.2 cm. The defect was slightly smaller on cross-sectional echocardiograms than at the time of operation. As the defect grew larger, the right ventricular dimension and the Qp/Qs became larger as well. Postoperatively, the right ventricular dimension was remarkably decreased, and the paradoxical movement of the interventricular septum (IVS) was normalized in the majority of the patients. Cross-sectional echocardiography is useful to diagnose ASD, to measure the size of the IAS defect, and to follow the clinical course.

Adolescent↗
PubMed1982

[Study on tricuspid regurgitation in Ebstein's anomaly using pulsed Doppler technique combined with two-dimensional echocardiography].

To investigate the localization of tricuspid regurgitant flow in Ebstein's anomaly, pulsed Doppler echocardiography (PDE) was performed on nine patients with or without associated cardiac lesions. The equipment used was characterized by the real time frequency analysis of Doppler signals obtained from the sampling sites confirmed on the cross-sectional images. We employed the apical four-chamber view or right ventricular inflow view in order to facilitate the sampling of Doppler signals from the three-sided heart chambers of this lesion. Doppler signals were recorded from several points in the functional right ventricle, atrialized right ventricle and right atrium. The PDE recording was made in conjunction with M-mode echocardiography at a paper speed of 50 mm per second. In eight of the nine patients, a systolic disturbed flow of wide band pattern was maximally located in the atrialized right ventricle in the vicinity of the tricuspid valve leaflets and had a delayed onset, which were seemed to be the findings characteristic of tricuspid regurgitation in Ebstein's anomaly. In the remaining one, a turbulent flow due to this lesion was obscured by a systolic jet of the associated ventricular septal defect in the vicinity of the tricuspid valve leaflet. In the right atrium, no disturbed flow of wide band pattern existed or only a faint abnormal blood flow was observed during systole. In the functional right ventricle, a smooth blood flow of the right ventricular inflow was recognized in diastole. In contrast, 15 patients with secondary tricuspid regurgitation revealed a holosystolic disturbed flow of wide band pattern maximally in the right atrium in the vicinity of the tricuspid valve leaflets. In eight healthy subjects, there was no systolic disturbed flow in the right atrium. Pulsed Doppler technique combined with two-dimensional echocardiography is thought useful to detect the localization of the disturbed flow in Ebstein's anomaly, thus contributing to the differentiation of various causes of tricuspid regurgitation.

Adult↗
PubMed1981

Clinical investigation of aortic insufficiency by means of pulsed Doppler echocardiography.

Pulsed Doppler echocardiography (PDE) was performed on 41 patients with aortic insufficiency (AI), isolated or associated with other cardiac diseases, using an ATL 500A pulsed Doppler system. The diagnosis was confirmed by angiocardiography in 25 cases. The purpose of the present study was to analyze the disturbed flow due to AI, to investigate the sensitivity of PDE to this lesion, and to compare with the angiographic severity of AI (Sellers). The transducer was placed on the left sternal border and the flow pattern was recorded at the aortic valve orifice and the proximal and distal left ventricular outflow tract (LVOT), using a strip chart recorded at a paper speed of 100 mm/sec. The specific feature of AI was a widely dispersed dot pattern which began at the aortic valve closure and extended to late diastole. The severity of AI was graded by supravalvular aortogram in 25 patients. In grades I and II, the abnormal dot pattern due to AI was mostly detected at the aortic valve orifice and the distal LVOT, but it was rather difficult to detect the disturbed flow at the proximal LVOT. In contrast, in grades III and IV, the disturbed flow was recorded at all the sampling sites; with severe aortic regurgitation, it was detected at a wider range in the left ventricular cavity. In grades I and II, the abnormal dot dispersion at the proximal LVOT was not so large at its onset in diastole but it tended to increase after the mitral valve opening, whereas in the majority of patients of grades III and IV, a large dot dispersion was recognized from its onset to late diastole. The typical flow pattern due to AI was detected at the LVOT in 38 out of 41 patients (92.7%). Moreover, it was detected in all the patients with angiographically proved AI except for 1 case of grade I (96.0%).

Adolescent↗
PubMed1981

Clinical study on the abnormal flow patterns in Ebstein's anomaly using pulsed Doppler echocardiography.

Pulsed Doppler echocardiography (PDE) was performed in 10 patients with Ebstein's anomaly and 10 cases of tricuspid regurgitation secondary to mitral stenosis. Distal atrialized right ventricle (ATRV): In all patients with Ebstein's anomaly, tricuspid regurgitation flow was recognized by PDE. In this lesion with moderate tricuspid regurgitation, a widely dispersed dot pattern was recorded during systole However, in the cases with severe tricuspid regurgitation a relatively smooth dot pattern was recognized. In the case with marked delay in pressure rise in the right ventricle, PDE showed a bimodal regurgitant flow pattern. The interval between the onset of QRS and that of tricuspid regurgitant flow with right ventricular pressure rise was measured. The interval corrected for heart rate ranged from 0.10 to 0.35 with an average of 0.19 +/- 0.08 sec. In the subjects with secondary tricuspid regurgitation, it ranged from 0.07 to 0.11 sec. This interval was significantly prolonged in Ebstein's anomaly as compared to that in secondary tricuspid regurgitation (p less than 0.001). Proximal ATRV: Tricuspid regurgitant flow was detected in 6 to 10 patients with Ebstein's anomaly. The disturbed flow was less apparent in the proximal ATRV than in the distal ATRV.

Adult↗