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Dive into the research topics where Takahiro Kozuka is active.

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Featured researches published by Takahiro Kozuka.


Circulation | 1982

Evaluation of tricuspid regurgitation by pulsed Doppler and two-dimensional echocardiography.

Kunio Miyatake; Mitsunori Okamoto; Naokazu Kinoshita; Mitsushige Ohta; Takahiro Kozuka; Hiroshi Sakakibara; Yasuharu Nimura

We analyzed tricuspid regurgitation noninvasively using ultrasonic pulsed Doppler and twodimensional echocardiography in 66 patients in whom tricuspid regurgitation was suspected from routine clinical evaluation. All of the patients also underwent right ventriculography. Ten healthy subjects served as controls. In 62 of 66 patients, the study was adequately performed. In 58 of 62 patients, pansystolic abnormal Doppler signals were detected in the right atrial cavity, and were interpreted to indicate tricuspid regurgitant flow. Two-dimensional echocardiograms in the parasternal four-chamber view demonstrated that the region in which the abnormal Doppler signals were detected was spindle-shaped and extended from the tricuspid orifice toward the right atrial posterior wall parallel to the interatrial septum. The severity of regurgitation was graded on a four-point scale, based on the distance reached by the abnormal signals from the tricuspid orifice toward the posterior wall. For comparison, the right ventriculograms were evaluated on a four-point scale similar to the Sellers classification of mitral regurgitation. The grades by the two methods matched exactly in 36 cases, differed by one level in 23 and by two levels in three. Thus, the two methods showed a good correspondence. Similar results were obtained for the grading based on the area covered by the abnormal signals. We conclude that noninvasive grading of tricuspid regurgitation by ultrasonic pulsed Doppler and two-dimensional echocardiography is practicable.


Cancer | 1991

Limitation of transcatheter arterial chemoembolization using iodized oil for small hepatocellular carcinoma. A study in resected cases

Chikazumi Kuroda; Masami Sakurai; Morito Monden; Taro Marukawa; Takuya Hosoki; Koh Tokunaga; Kenichi Wakasa; Jun Okamura; Takahiro Kozuka

The radiologic and histologic findings are presented of the resection of 14 small hepatocellular carcinomas (HCC), less than 2 cm in maximum diameter, after transcatheter arterial chemoembolization (TCE) using iodized oil. The effect of TCE on small HCC depended on the morphologic type of the tumors. When no extracapsular invasion of tumor cells occurred, TCE was extremely effective against encapsulated tumors. However, in nine of the 14 resected specimens, viable tumor cells remained in or around the tumor. The authors suggest that small HCC are not always curable with TCE alone and that a multi‐disciplinary approach is necessary for patients with small HCC.


Brain Research | 1991

Regional distribution of the cells expressing glycine receptor β subunit mRNA in the rat brain

Masahiro Fujita; Kohji Sato; Makoto Sato; Toshihiko Inoue; Takahiro Kozuka; Masaya Tohyama

The expression of mRNA of the beta subunit of the glycine receptor was investigated in the rat by in situ hybridization histochemistry using an oligonucleotide probe specific to the sequence of the beta subunit. Neurons expressing beta subunit mRNA were widely and abundantly distributed in the rat brain from the olfactory bulb to the spinal cord. The pattern of distribution of cells containing beta subunit mRNA in the lower brainstem was very similar to that of cells containing alpha 1 subunit mRNA. In addition, beta subunit mRNA was strongly expressed by the neurons of the cerebral cortex, hippocampal formation and diencephalon as well as by the Purkinje cells where alpha 1 subunit mRNA expression is rare. These findings indicated that the glycine receptor is heterogeneous. The sites where strong labeling was noted were as follows. In the forebrain and diencephalon, strongly labeled neurons were abundant in the olfactory region, hippocampal formation, cerebral cortex, and thalamus. In the hippocampal formation, neurons in the subiculum, pyramidal cells in Ammons horn, and neurons in the polymorphic layer of the dentate gyrus were strongly labeled. In the thalamus, the anterodorsal, reticular, parafascicular, and the subthalamic nuclei were strongly labeled. In the brainstem, the red nucleus, almost all of the motor neurons in the cranial motor nuclei innervating striated muscles, the trigeminal mesencephalic nucleus, the ventral tegmental nucleus of Gudden, and the pontine nucleus were strongly labeled. In the cerebellum, Purkinje cells in the Purkinje cell layer and all of the cerebellar nuclei were strongly labeled.


Circulation | 1975

Transfemoral plug closure of patent ductus arteriosus. Experiences in 61 consecutive cases treated without thoracotomy.

K Sato; M Fujino; Takahiro Kozuka; Y Naito; Soichiro Kitamura; Susumu Nakano; C Ohyama; Yasunaru Kawashima

We successfully closed the isolated patent ductus arteriosus in 58 of 61 consecutive patients using the transfemoral-catheter method originally introduced by Porstmann in 1968. To perform this technique more safely and reliably, some instrumental and technical improvements were made. The indications for this method have been expanded to include the cylindrical or window-type ductus as well as the conical-shaped ductus. Classification into three groups of the configuration of the ductus by angiography has been useful in selecting the shape of the closing plug. Whenever feasible, we consider the catheter technique to be the method of choice to close the ductus.


Journal of Computer Assisted Tomography | 1994

Chronic eosinophilic pneumonia: evolution of chest radiograms and CT features.

Hidemi Ebara; Junpei Ikezoe; Takeshi Johkoh; Nobuaki Kohno; Noriyuki Takeuchi; Takahiro Kozuka; Osamu Ishida

Objective Our object is to describe and compare the findings on plain chest radiographs and CT scans in patients with chronic eosinophilic pneumonia of varying duration, as judged by their clinical history. Materials and Methods We retrospectively reviewed the initial chest radiographs and initial CT scans that were obtained before treatment with corticosteroid in 17 patients with pathologically proven or clinically diagnosed chronic eosinophilic pneumonia. Results Eleven of the 17 patients showed predominantly peripheral patchy or confluent consolidation with or without ground-glass opacities on chest radiography. Sixteen patients, on the other hand, showed various types of abnormalities with peripheral predominance on CT. The seven patients in whom the initial CT was performed within 1 month after the onset of symptoms had dense confluent consolidation (7/7) with or without ground-glass opacities. When the initial CT was performed 1–2 months after onset of symptoms, inhomogeneous patchy consolidation or nodules (5/7) or ground-glass opacities (2/7) were observed. When the initial CT was performed >2 months after the onset of symptoms, streaky or band-like opacities (1/3) or lobar atelectasis (1/3) was seen. Conclusion Patients with chronic eosinophilic pneumonia show an evolution of CT features at varying time intervals after the onset of disease.


American Heart Journal | 1985

Thallium perfusion and cardiac enzyme abnormalities in patients with familial hypertrophic cardiomyopathy.

Seiki Nagata; Yung-Dae Park; Tetsuhiro Minamikawa; Chikao Yutani; Tetsuro Kamiya; Tsunehiko Nishimura; Takahiro Kozuka; Hiroshi Sakakibara; Yasuharu Nimura

Twelve patients of five families with familial hypertrophic cardiomyopathy were examined. Within each family, the older patients showed dilation or diminished contraction of the left ventricle by echocardiography or angiocardiography more frequently than did younger patients. LDH1 fraction (lactic dehydrogenase isoenzyme) and MB-CPK (creatinine phosphokinase isoenzyme) were increased in 7 of 10 patients. Thallium-201 myocardial scintigraphy showed perfusion defect or hypoperfusion in 9 of 10 patient. Eleven cases demonstrated remarkable hypertrophy at the macroscopic level. Marked fibrosis was observed in all 5 of the 11 patients whose histologic findings were obtained. In two necropsy cases, disarray was found throughout the right and left ventricles and the pattern of fibrosis was massive. These findings were different from those of ordinary hypertrophic cardiomyopathy. It is possible that each patient with familial hypertrophic cardiomyopathy may develop more prominent thallium and enzyme abnormalities as he becomes older, regardless of whether he develops a dilated cardiomyopathy picture.


American Journal of Cardiology | 1977

Left ventricular function in patients with coronary arteritis due to acute febrile mucocutaneous lymph node syndrome or related diseases

Soichiro Kitamura; Yasunaru Kawashima; Kanji Kawachi; Masaoki Fujino; Takahiro Kozuka; Tsuyoshi Fujita; Hisao Manabe

Abstract Reports of a mucocutaneous lymph node syndrome that frequently affects the coronary arteries have been increasing in Japan and other countries including the United States. Twelve patients with a documented history of mucocutaneous lymph node syndrome or a related coronary arteritis were studied with right and left heart catheterization, cardiac output measurements, left cineventriculography and selective coronary arteriography. These patients were separated into two groups on the basis of coronary arteriographic findings. Group 1 comprised six patients with normal coronary arteriograms; group 2 included the remaining six patients with coronary arterial aneurysm or occlusion. Left ventricular function differed in the two groups. It remained essentially normal in group 1 whereas decreased ejection fraction, increased end-diastolic volume, elevated end-diastolic pressure or mitral regurgitation were evident in four of the six patients in group 2. Two ventriculographic abnormalities were identified: (1) regional contraction abnormality secondary to myocardial infarction, and (2) generalized hypokinesia without electrocardiographic evidence of infarction, probably caused by myocarditis resulting from arteritis. Two patients with severe coronary arterial obstruction and myocardial infarction underwent successful aortocoronary bypass grafting. Postoperatively both had patency of all grafts and one had improved left ventricular function. These experiences have first shown the feasibility and significance of surgical management for selected patients with coronary arterial lesions due to coronary arteritis caused by the mucocutaneous lymph node syndrome or related diseases.


Journal of the American College of Cardiology | 1990

Assessment of the intrapulmonary ventilation-perfusion distribution after the Fontan procedure for complex cardiac anomalies: Relation to pulmonary hemodynamics

Tohru Matsushita; Hikaru Matsuda; Minoru Ogawa; Kiyoshi Ohno; Tetsuya Sano; Susumu Nakano; Yasuhisa Shimazaki; Kazuya Nakahara; Jun Arisawa; Takahiro Kozuka; Yasunaru Kawashima; Hyakuji Yabuuchi

In 12 patients who underwent the Fontan procedure for complex cardiac anomalies, lung scanning with xenon-133 was performed to assess the intrapulmonary ventilation-perfusion distribution, and comparison was made with a control group. All data were then analyzed in relation to either pre- or postoperative pulmonary hemodynamic data. In ventilation scans, the intrapulmonary distribution in the right lung was almost normal. In perfusion scans, an abnormal increased upper to lower lobe perfusion ratio greater than the normal value found in the control group was noted in seven patients (58.3%). There was a significant correlation (p less than 0.02) between the upper to lower lobe perfusion ratio and postoperative pulmonary vascular resistance. Furthermore, this perfusion ratio correlated inversely with the preoperative (p less than 0.005) and postoperative (p less than 0.02) right pulmonary artery area index, defined as the ratio of cross-sectional area to the normal value. Of five patients with less than 90% arterial oxygen saturation, four showed an abnormal distribution of pulmonary blood flow greater than the normal perfusion ratio. No patient had evidence of a pulmonary arteriovenous fistula by the echocardiographic contrast study. These results suggest that abnormal distribution of pulmonary blood flow to the upper lung segment may develop in patients after the Fontan procedure, and that insufficient size of the pulmonary artery before operation and the consequent postoperative elevation of pulmonary vascular resistance may be responsible for this perfusion abnormality.


Journal of Computer Assisted Tomography | 1992

CT and MRI of Siderotic Regenerating Nodules in Hepatic Cirrhosis

Takamichi Murakami; Hironobu Nakamura; Shinichi Hori; Katsuyuki Nakanishi; Takashi Mitani; Kyo Tsuda; Takahiro Kozuka; Kenichi Wakasa; Morito Monden

The demonstration by CT of siderotic regenerating liver nodules in cirrhosis was evaluated and compared with that of MR imaging retrospectively in 27 patients with histologically diagnosed hepatic cirrhosis. Only in one of the two patients with marked iron deposits in regenerating nodules did CT demonstrate multiple high density nodules. In the other patient with marked iron deposits and in seven of the nine patients with moderate iron deposits, the liver parenchyma on CT was demonstrated as heterogeneous and of slightly high density without focal nodules. In 8 patients with mild to moderate iron deposits and in the 10 with no iron deposits, the liver parenchyma was homogeneous on CT. Multiple low intensity nodules in the liver were seen on fast low-angle shot (FLASH) MR images in all 17 patients with iron deposits in regenerating nodules. No low intensity nodules were seen on FLASH MR images in the 10 patients with no iron deposits. If there are iron deposits above a certain level, siderotic regenerating nodules may appear as nodules of high density on CT or as heterogeneous regions of high density liver parenchyma. Magnetic resonance is more sensitive than CT in demonstrating siderotic regenerating nodules.


Acta Radiologica | 1995

Detectability of hypervascular hepatocellular carcinoma by arterial phase images of MR and spiral CT.

Takamichi Murakami; Tonsok Kim; Hiromichi Oi; Hironobu Nakamura; Hideji Igarashi; Masaki Matsushita; Jun Okamura; Takahiro Kozuka

The ability of arterial phase images of breath-hold MR imaging and spiral CT to detect hypervascular hepatocellular carcinomas (HCCs) was evaluated. Prior to transcatheter arterial chemoembolization (TACE) with iodized oil, MR images and spiral CT during i.v. bolus injection of contrast medium (IV-MR imaging and IV-spiral CT) and spiral CT during intraarterial injection of contrast media through catheter (IA-spiral CT) of the entire liver were obtained in 24 consecutive patients with 93 HCCs. In the detection of HCCs less than 1 cm in diameter, IA-spiral CT (87.3%) was superior to IV-MR imaging (63.5%) and IV-spiral CT (54.0%) (p < 0.001). There was no significant difference in detectability in any tumor size between IV-MR imaging and IV-spiral CT. IA-spiral CT was the best for detecting hypervascular HCCs, and there was no significant difference between IV-MR imaging and IV-spiral CT.

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