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Dive into the research topics where Hiroyuki Koba is active.

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Featured researches published by Hiroyuki Koba.


Investigative Radiology | 2000

Lobar distribution of emphysema in computed tomographic densitometric analysis.

Tsukasa Saitoh; Hiroyuki Koba; Noriharu Shijubo; Hiroshi Tanaka; Fumiko Sugaya

RATIONALE AND OBJECTIVES The aims of this study were to determine the extent of emphysema in individual lobes and to investigate whether the lobar distribution of emphysema influences pulmonary function. METHODS Helical CT and pulmonary function tests were performed in 50 emphysema patients. Percentages of low attenuation volume (extent of emphysema) were calculated for each lobe by using CT densitometric analysis. RESULTS The extent of emphysema of the whole lung in these patients was 44%. Airflow limitation (r = -0.82, P<0.0001) and residual volume (r = -0.52, P<0.01) were closely correlated with the extent of emphysema in both lower lobes. Diffusing capacity (r = -0.61, P<0.0001) was closely correlated with the extent of emphysema in both upper lobes. On the basis of the lobar distribution of emphysema as determined by CT densitometry, we divided these emphysema patients into predominantly upper-lobe disease and predominantly lower-lobe disease groups. The predominantly lower-lobe disease group had significantly greater severe airflow limitation (P<0.0001), greater residual volume (P<0.01), and greater total lung capacity (P<0.05) than did the predominantly upper-lobe disease group. CONCLUSIONS CT densitometry showed a distinct lobar distribution of emphysema. Pulmonary function is significantly different between predominantly upper- and lower-lobe emphysema groups.


European Respiratory Journal | 1994

Chronic eosinophilic pneumonia progressing to lung fibrosis

K Yoshida; Noriharu Shijubo; Hiroyuki Koba; Y Mori; M Satoh; T Morikawa; Shosaku Abe

A 65 year old Japanese man was hospitalized with fever. Opacities distributed mainly in the subpleural regions were found on chest computed tomographic scan (CT), and these promptly cleared with corticosteroid therapy. Four years later, he presented with severe eosinophilia. Both chest X-ray and high resolution CT scan showed ground-glass opacities and honeycombing, suggesting lung fibrosis. A lung biopsy demonstrated intra-alveolar eosinophil infiltration, interstitial thickening with eosinophil infiltration, and a widely-distributed desquamative interstitial pneumonia-like reaction. With corticosteroid therapy, the ground-glass opacities decreased with a corresponding clinical improvement, although lung honeycombing and blood eosinophilia remained. In this case, circulating intercellular adhesion molecule-1 and circulating and bronchoalveolar lavage fluid eosinophil granule proteins were felt to be more effective markers for evaluating disease activity than the blood eosinophil number.


European Respiratory Journal | 1996

Relationships between radiological pattern and cell-mediated immune response in Mycoplasma pneumoniae pneumonia

H Tanaka; Hiroyuki Koba; S Honma; F Sugaya; Shosaku Abe

The aim of this study was to determine the relationship between the radiological pattern of Mycoplasma pneumoniae and the level of cell-mediated immunity of the host. Computed tomographic (CT) scans of the chest and the results of the purified protein derivative (PPD) test were studied during the acute stage of infection in 54 patients with M. pneumoniae pneumonia. The CT findings were used to divide the patients into two groups: one group had a predominance of nodular opacities with a centrilobular distribution (Group N; n = 29); and the other showed a predominance of an airspace consolidation (Group C; n = 25). Forty out of 54 subjects had negative tuberculin skin tests ( < 10 mm induration). The positive rate of PPD reaction was higher in Group N (13 out of 29) compared to Group C (1 out of 25) (p = 0.0005); whilst pleural effusion appeared more frequently in Group C (10 out of 25) than in Group N (3 out of 29) (p = 0.023). There was no significant difference between Groups N and C in white blood cell and lymphocyte counts, level of antibodies to M. pneumoniae in sera, and severity of the disease. These findings suggest that the characteristics of the host cell-mediated immunity might influence the pattern of pulmonary lesions in M. pneumoniae infection.


Journal of Computer Assisted Tomography | 1998

Pulmonary alveolar microlithiasis : High-resolution CT and MR findings

Hideaki Hoshino; Hiroyuki Koba; Shin-Ichiroh Inomata; Keizo Kurokawa; Yuji Morita; Kazuhiro Yoshida; Hidenari Akiba; Shosaku Abe

We report the high-resolution CT (HRCT) and MR findings in a case of pulmonary alveolar microlithiasis. HRCT revealed that the black pleural line on a chest radiograph was caused not by subpleural cysts but by a fat-dense layer between ribs and the calcified parenchyma. MRI showed both lower zones with diffusely increased signal intensity on T1-weighted images. We speculated it was caused by the accumulation of small-sized calcific particles.


Cancer | 1983

A case of bronchioloalveolar carcinoma ultrastructural and lipid‐biochemical studies

Mitsushige Nakamura; Kiyoharu Itoh; Yasuhito Honda; Hiroyuki Koba; Mitsuo Asakawa; Akira Suzuki; Yutaka Yoshida; Masaaki Satoh; Toyoaki Akino

A case of bronchioloalveolar carcinoma was studied electron microscopically and lipid biochemically. Electron microscopic examination revealed that the tumor was composed of three different types of cells, undifferentiated cells, cells possessing lamellar inclusion bodies within the cytoplasm, and cells containing mucus droplets. The characteristic findings in the phospholipid profiles of this case of bronchioloalveolar carcinoma were a high content of saturated classes of phosphatidylcholine, especially of the dipalmitoyl type, and the occurrence of appreciable amounts of phosphatidylglycerol. These observations indicate that some of the tumor cells examined in this study had the characteristic feature of alveolar type II cell differentiation which is responsible for production of pulmonary surface‐active materials. The value of phospholipid analysis in assessing such tumors is emphasized.


The Open Respiratory Medicine Journal | 2012

Classification of Centrilobular Emphysema Based on CT-Pathologic Correlations

Mamoru Takahashi; Gen Yamada; Hiroyuki Koba; Hiroki Takahashi

Introduction: Centrilobular emphysema (CLE) is recognized as low attenuation areas (LAA) with centrilobular distribution on high-resolution computed tomography. The LAA often exhibit a variety of shape or sharpness of border. This study was performed to elucidate the relationship between morphological features of LAA and pathological findings in CLE. Materials and Methods: The inflated-fixed lungs from 50 patients with CLE (42 males, 8 females; 14 operated, 36 autopsied) were examined by a method of CT-pathologic correlations that consisted of three steps. The first, CT images of the sliced lungs of the inflated-fixed lung specimens were examined on the shape and the peripheral border of each LAA. The second, the sliced lungs were radiographed in contact with high magnification. The third, the surface of the sliced lungs was observed by using stereomicroscopy. The views at low magnification of stereomicroscope were compared with the radiographs and the CT images of the same sample. Results: Using CT-pathologic correlations, LAAs of CLE were classified into three types as follows; round or oval shape with well-defined border (Type A), polygonal or irregular shape with ill-defined border and less than 5 mm in diameter (Type B), and irregular shape with ill-defined border and 5 mm or over in diameter (Type C). Type A, Type B and Type C LAA were mainly related to dilatation of bronchioles, destruction of proximal part of alveolar ducts, and destruction of distal part of alveolar ducts, respectively. Type A, Type B and Type C were dominant LAA in 5 (10%), 29 (58%) and 12 (24%) patients, respectively. However, remained 4 patients (8%) did not show dominant LAA type. Conclusion: Morphological features of LAA in CLE may depend on dilatation or destruction of certain parts of the secondary lobule. Type B LAA was the commonest type in CLE.


The Open Respiratory Medicine Journal | 2013

Computed tomography-based centrilobular emphysema subtypes relate with pulmonary function.

Mamoru Takahashi; Gen Yamada; Hiroyuki Koba; Hiroki Takahashi

Introduction: Centrilobular emphysema (CLE) is recognized as low attenuation areas (LAA) with centrilobular pattern on high-resolution computed tomography (CT). However, several shapes of LAA are observed. Our preliminary study showed three types of LAA in CLE by CT-pathologic correlations. This study was performed to investigate whether the morphological features of LAA affect pulmonary functions. Materials and Methods: A total of 73 Japanese patients with stable CLE (63 males, 10 females) were evaluated visually by CT and classified into three subtypes based on the morphology of LAA including shape and sharpness of border; patients with CLE who shows round or oval LAA with well-defined border (Subtype A), polygonal or irregular-shaped LAA with ill-defined border (Subtype B), and irregular-shaped LAA with ill-defined border coalesced with each other (Subtype C). CT score, pulmonary function test and smoking index were compared among three subtypes. Results: Twenty (27%), 45 (62%) and 8 cases (11%) of the patients were grouped into Subtype A, Subtype B and Subtype C, respectively. In CT score and smoking index, both Subtype B and Subtype C were significantly higher than Subtype A. In FEV1%, Subtype C was significantly lower than both Subtype A and Subtype B. In diffusing capacity of lung for carbon monoxide, Subtype B was significantly lower than Subtype A. Conclusion: The morphological differences of LAA may relate with an airflow limitation and alveolar diffusing capacity. To assess morphological features of LAA may be helpful for the expectation of respiratory function.


Pulmonary Research and Respiratory Medicine – Open Journal | 2017

Significance of Combined Emphysema in Idiopathic Pulmonary Fibrosis and Serum Surfactant Protein-D as a Prognostic Factor

Keiki Yokoo; Masanori Shiratori; Kimiyuki Ikeda; Yasuaki Umeda; Mitsuo Otsuka; Hirotaka Nishikiori; Hirofumi Chiba; Hiroyuki Koba; Hiroki Takahashi

1Department of Respiratory Medicine and Allergology, Sapporo Medical University School of Medicine, South-1 West-17, Chuo-ku, Sapporo 060-8556, Japan 2Department of Respiratory Medicine, Teine Keijinkai Hospital, 1-40, Maeda 1-12, Teine-ku, Sapporo 006-8555, Japan *Corresponding author Masanori Shiratori, MD Associate Professor Department of Respiratory Medicine and Allergology Sapporo Medical University School of Medicine South-1 West-17 Chuo-ku, Sapporo 060-8556, Japan Tel. +81-11-611-2111 (ext. 32390) Fax: +81-11-613-1543 E-mail: [email protected]


American Journal of Respiratory and Critical Care Medicine | 2000

Serum Surfactant Proteins A and D as Prognostic Factors in Idiopathic Pulmonary Fibrosis and Their Relationship to Disease Extent

Hiroki Takahashi; Takuya Fujishima; Hiroyuki Koba; Seiji Murakami; Keizo Kurokawa; Yoshie Shibuya; Masanori Shiratori; Yoshio Kuroki; Shosaku Abe


Internal Medicine | 2002

Pulmonary MALT lymphoma with amyloid production in a patient with primary Sjögren's syndrome.

Naoto Nakamura; Gen Yamada; Takayuki Itoh; Akihiro Suzuki; Shiho Morita-Ichimura; Shin Teramoto; Noriharu Shijubo; Hiroyuki Koba; Masaaki Satoh; Shosaku Abe

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Shosaku Abe

Sapporo Medical University

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Hiroki Takahashi

Sapporo Medical University

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Noriharu Shijubo

Sapporo Medical University

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Mitsuo Asakawa

Sapporo Medical University

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Gen Yamada

Sapporo Medical University

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Hiroshi Tanaka

Sapporo Medical University

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Masaki Mori

Sapporo Medical University

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Tsukasa Saitoh

Sapporo Medical University

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