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Akihito Yokoyama

Publications and source records attributed to Akihito Yokoyama.

At least 19 recordsLinked to original sources
PubMed2006

Overproduction of collagen and diminished SOCS1 expression are causally linked in fibroblasts from idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and often fatal pulmonary disorder, and its pathology is characterized by parenchymal fibrosis. To investigate the characteristics of fibroblasts in IPF, we obtained eight fibroblast cell lines from lungs with IPF and eight lines from normal lungs. We found that the fibroblasts from IPF spontaneously produced higher amounts of type I collagen and had lower expression levels of SOCS1 than fibroblasts from normal lung. By using mouse fibroblasts, we demonstrated the causal relationship between them: the deficiency of SOCS1 in fibroblasts resulted in increased collagen production, whereas overexpression of SOCS1 suppressed collagen production. IFN-gamma suppressed spontaneous collagen production even in SOCS1-deficient fibroblasts, indicating that IFN-gamma inhibition is SOCS1-independent. In contrast, IFN-gamma suppressed the increase of collagen production induced by IL-4 in wild type fibroblasts but not SOCS1-deficient fibroblasts, suggesting IFN-gamma acted exclusively via SOCS1 in this case. Following IFN-gamma stimulation, the amount of SOCS1 mRNA expressed by IPF fibroblasts was comparable to that of normal fibroblasts. Thus, the extent of SOCS1 increase after stimulation by IFN-gamma was significantly higher in IPF fibroblasts. The extent to which IFN-gamma inhibited collagen production was also larger in IPF fibroblasts than in normal fibroblasts. These results suggest that the exaggerated production of collagen observed in fibroblasts from IPF is causally related to the diminished expression of SOCS1, and IPF fibroblasts are more susceptible to IFN-gamma because of decreased expression of SOCS1.

Animals↗
PubMed2006

Effect of CPAP on brachial-ankle pulse wave velocity in patients with OSAHS: an open-labelled study.

Pulse wave velocity (PWV) is a good indicator of arterial stiffness and an important predictor of cardiovascular events. Recent studies have revealed that PWV increases in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) and it also correlates with its severity. However, the therapeutic effect of continuous positive airway pressure (CPAP) on PWV remains undetermined. To clarify this point, we started CPAP treatment on 17 OSAHS patients. Brachial-ankle PWV was measured before starting CPAP, and at 2 months and 4 months after the start of CPAP. Before the CPAP treatment, mean brachial-ankle PWV of the patients was 15.6+/-0.6 m/s, and mean Epworth sleepiness scale (ESS) score was 8.6+/-1.0. Brachial-ankle PWV was found to positively correlate with heart rate, systolic and diastolic blood pressures, mean blood pressure, and arousal index. During the study period, the CPAP treatment did not have a significant effect on heart rate, blood pressures and serum total cholesterol levels. However, it significantly improved ESS score at 4 months after the start of CPAP (P=0.001), while it effectively decreased brachial-ankle PWV at 2 months and at 4 months after the start of CPAP (P=0.010 and P=0.027, respectively). The CPAP treatment was shown to decrease brachial-ankle PWV without affecting blood pressures in OSAHS patients. Although the precise mechanism for this effect is unclear, our finding suggests a close relationship between OSAHS and arterial stiffness, while also reemphasizing the clinical importance of CPAP treatment.

Ankle↗
PubMed2006

Effect of inhaled bronchodilators on air trapping in patients with stable asthma.

Air trapping is frequently observed during high-resolution computed tomography (HRCT) of patients with asthma, but whether the condition is reversible has not been thoroughly investigated. The aim of the present study was to evaluate reversibility of air trapping in response to bronchodilator. Ten never-smokers with stable asthma enrolled in the study. Spirometry and HRCT were performed before and after bronchodilator inhalation. Air trapping remained unchanged, although significant reversibility of FEV(1) was observed. Air trapping scores correlated significantly with airway wall thickness. These observations suggest that air trapping is irreversible and that it represents structural remodeling of small airways in patients with stable asthma.

Administration, Inhalation↗
PubMed2006

Novel orthotopic implantation model of human malignant pleural mesothelioma (EHMES-10 cells) highly expressing vascular endothelial growth factor and its receptor.

Malignant pleural mesothelioma (MPM) is closely related to exposure to asbestos, and a rapid increase in the number of MPM patients in Japan is estimated in the years 2010-2050. The purpose of the present study was to establish a clinically relevant animal model that shows human patient-like progression of MPM. Here, we demonstrate that a human MPM cell line (EHMES-10) inoculated orthotopically (thoracic cavity) into severe combined immunodeficiency (SCID) mice produces highly vascularized thoracic tumors with pleural dissemination and bloody pleural effusions by 5 weeks, suggesting a patient-like progression of this cell line after orthotopic inoculation. EHMES-10 cells overexpressed vascular endothelial growth factor (VEGF), a molecule responsible for malignant effusions, and its receptor. Treatment with cisplatin, but not gemcitabine, significantly inhibited the production of pleural effusions, but it was not effective for thoracic tumors, consistent with chemotherapy refractory characteristics of MPM in patients. Our patient-like orthotopic model using EHMES-10 cells overexpressing VEGF and its receptor may be useful for examining the molecular pathogenesis of MPM and may contribute to the development of novel treatment strategies for MPM.

Animals↗
PubMed2006

Anti-tumor effect of the anti-KL-6/MUC1 monoclonal antibody through exposure of surface molecules by MUC1 capping.

Human polymorphic epithelial mucin (MUC1) is a heavily glycosylated large protein that is frequently overexpressed on the surface of many human adenocarcinomas. Studies using monoclonal antibodies (mAb) identified MUC1 as a tumor-associated antigen that has been intensely studied as a target for cancer immunotherapy. We previously identified a mouse IgG(1) mAb that recognizes a sialylated sugar chain, designated as KL-6, classified in 'Cluster 9 (MUC1)'. Using the anti-KL-6 mAb, we investigated antitumor effects of anti-MUC1 mAb on breast cancer cell lines expressing MUC1 abundantly. We showed that anti-KL-6 mAb induced capping of MUC1 and facilitated E-cadherin-mediated cell-cell interaction in the breast cancer cell lines YMB-S and ZR-75-1S, which proliferate in suspension culture without aggregation. Moreover, anti-KL-6 mAb enhanced the cytotoxic activity of lymphokine-activated killer cells. These results indicate that the capping of MUC1 restores cell surface proteins, such as adhesion molecules and tumor antigens, to work in cell-cell interactions, leading to inhibition of tumor proliferation due to cell-cell adhesion and increased accessibility to effector cells that are needed to kill tumor cells.

Animals↗
PubMed2006

Prognostic value of circulating KL-6 in idiopathic pulmonary fibrosis.

OBJECTIVE: Circulating levels of KL-6, a high MW glycoprotein (MUC1 mucin), are elevated in a majority of patients with a number of interstitial lung diseases, including idiopathic pulmonary fibrosis (IPF). However, KL-6 levels vary from patient to patient. The aim of the present study was to determine whether the serum KL-6 level at the time of diagnosis predicts prognosis in IPF. METHODS: The relationship between clinical variables and prognosis in 27 patients with IPF were analysed retrospectively. The diagnosis was made by histological examination (n = 16) or on clinical findings including high-resolution CT scanning (n = 11). All patients were followed up for at least 3 years. Variables such as age, FVC%, PaO(2) at rest, initial LDH level, C-reactive protein and KL-6 were used for analysis. RESULTS: At the cut-off level determined by receiver operating characteristic curves, LDH and KL-6 showed a significant correlation with the patient's prognosis by univariate analysis. However, multivariate analysis revealed that only KL-6 was a predictor of prognosis. The patients were categorized by their serum KL-6 levels (as above or below the cut-off level of 1000 U/mL) and their survival estimated using the Kaplan-Meier method. The difference in median survival between the two groups was significant. The median survival of patients with low KL-6 was more than 36 months, whereas that of patients with high KL-6 was only 18 months. CONCLUSION: These results suggest that initial evaluation of serum KL-6 level can predict survival in patients with IPF.

Antigens, Neoplasm↗
PubMed2005

Circulating aminopeptidase N/CD13 is an independent prognostic factor in patients with non-small cell lung cancer.

PURPOSE: Aminopeptidase N, also known as CD13, has important roles in tumor metastasis and angiogenesis. Its expression in tumor tissue has been reported to be associated with poor prognosis. However, the clinical significance of circulating aminopeptidase N/CD13 in patients with solid tumors is unknown. We previously developed an aminopeptidase N/CD13-specific monoclonal antibody (mAb) MH8-11, which inhibits cell motility and angiogenesis in vitro. The aim of this study was to evaluate the clinical significance of circulating aminopeptidase N/CD13 protein detected by mAb MH8-11 in patients with non-small cell lung cancer (NSCLC). EXPERIMENTAL DESIGN: We used electrochemiluminescence immunoassay with mAb MH8-11 to determine circulating aminopeptidase N/CD13 levels in 90 healthy volunteers and 90 patients with NSCLC. Circulating aminopeptidase N/CD13 levels were measured in sera taken before treatment and evaluated for a relationship with clinical outcomes. RESULTS: A significant correlation was found between tumor progression and serum aminopeptidase N/CD13 concentrations (r=0.23, P=0.029). High serum aminopeptidase N/CD13 levels (n=17) were associated with advanced stage (P=0.004) or poor performance status (P=0.001). The overall survival rate for patients with high serum aminopeptidase N/CD13 levels (n=17) was significantly less than that of patients with low serum aminopeptidase N/CD13 levels (n=73, P<0.0001). In a multivariate survival analysis in patients with NSCLC, serum aminopeptidase N/CD13 levels had an independent influence on survival (relative risk, 4.1; 95% confidence interval, 1.9-8.8). CONCLUSIONS: Our data suggest that a high level of circulating aminopeptidase N/CD13 at diagnosis is an independent prognostic factor in patients with NSCLC.

Antibodies, Monoclonal↗
PubMed2005

KL-6, a human MUC1 mucin, promotes proliferation and survival of lung fibroblasts.

The serum level of KL-6, a MUC1 mucin, is a clinically useful marker for various interstitial lung diseases. Previous studies demonstrated that KL-6 promotes chemotaxis of human fibroblasts. However, the pathophysiological role of KL-6 remains poorly understood. Here, we further investigate the functional aspects of KL-6 in proliferation and apoptosis of lung fibroblasts. KL-6 accelerated the proliferation and inhibited the apoptosis of all human lung fibroblasts examined. An anti-KL-6 monoclonal antibody counteracted both of these effects induced by KL-6 on human lung fibroblasts. The pro-fibroproliferative and anti-apoptotic effects of KL-6 are greater than and additive to those of the maximum effective concentrations of platelet-derived growth factor, basic fibroblast growth factor, and transforming growth factor-beta. These findings indicate that increased levels of KL-6 in the epithelial lining fluid may stimulate fibrotic processes in interstitial lung diseases and raise the possibility of applying an anti-KL-6 antibody to treat interstitial lung diseases.

Antibodies, Monoclonal↗
PubMed2005

Metastatic renal cell carcinoma presenting as multiple pleural tumours.

A 66-year-old man was admitted with dyspnoea. Chest X-ray and chest computed tomography (CT) demonstrated a left-sided pleural effusion and multiple tumours, suggesting malignant mesothelioma in the left pleural space, but there were no pulmonary lesions. However, abdominal CT revealed a right renal tumour. An ultrasonography-guided needle biopsy of the pleural mass provided evidence of metastatic renal cell carcinoma (RCC). The pleural lesions dramatically decreased in size following right radical nephrectomy and subsequent interferon-alpha treatment. While the thorax is a frequently affected site of RCC, sole pleural metastases are rare and are often secondary to lung involvement. Batson's plexus, a network of vertebral valve-less veins with multiple connections, is likely responsible for the contralateral pleural metastases of RCC.

Aged↗
PubMed2005

Thymic carcinoma originating from the mid-posterior mediastinum.

An unusual thymic carcinoma in a 74-year-old woman is described. Initial chest CT revealed a mass at the mid-posterior mediastinum. Transbronchial fine needle biopsy of the mass failed to provide a definite diagnosis. The mass was treated as a malignant mediastinal tumour, and chemoradiotherapy was performed as initial treatment. The patient died 5 years after receiving primary treatment. The results of postmortem microscopic examination, including immunohistochemical study with CD5 antibody, were consistent with thymic carcinoma. This case is interesting in that the mid-posterior mediastinum is the site where thymic carcinoma is least likely to originate.

Aged↗
PubMed2005

Hemoperitoneum secondary to spontaneous rupture of hepatic metastasis from lung cancer.

We describe a rare case of hemoperitoneum secondary to spontaneous rupture of hepatic metastasis from lung cancer. A 72-year-old man with non-small cell lung cancer was admitted to our hospital with sudden onset of right upper abdominal pain and hypovolemic shock. Laboratory tests showed severe anemia. Abdominal contrast-enhanced computed tomography revealed massive ascites and multiple liver metastases. Rupture of a metastatic liver tumor was suspected. Only palliative therapy was performed. The patient's general condition gradually worsened, and he died 2 months after admission. Autopsy examination revealed hemoperitoneum due to a ruptured metastatic liver tumor originating from pulmonary squamous cell carcinoma.

Aged↗
PubMed2005

Neutropenic enterocolitis in lung cancer: a report of two cases and a review of the literature.

The first patient, a 68-year-old woman, presented neutropenic fever and hemorrhagic diarrhea on the sixth day of a combination chemotherapy of carboplatin and paclitaxel. The second patient, a 30-year-old man, presented neutropenia and diarrhea on the tenth day of the second cycle of a combination chemotherapy of cisplatin and vinorelbine. In both patients, abdominal computed tomography scan showed thickening of the colon wall and pericolic edema, and the ultrasonography revealed echogenic thickening of the colon walls. These findings confirmed the diagnosis of neutropenic enterocolitis. After the treatments, we changed the anticancer drug regimen; and successfully achieved partial responses.

Adenocarcinoma↗
PubMed2005

Two cases of primary pulmonary osteosarcoma.

Two cases of primary pulmonary osteosarcoma are presented. In both cases, chest computed tomography revealed a calcified pulmonary mass and technetium-99m methylene diphosphonate bone scintigraphy showed intense uptake in the pulmonary mass. Primary pulmonary osteosarcoma was suspected on the basis of these radiographic findings. Microscopic examination of tumor specimens obtained by needle biopsy revealed histologic features of osteosarcoma, and this diagnosis was confirmed by postmortem examination of a second specimen in each case. Radiographic and histopathological findings enabled us to diagnose primary pulmonary osteosarcoma, which is one of the rarest types of cancer.

Aged↗
PubMed2005

Polymorphism of the MUC1 mucin gene is associated with susceptibility to lung adenocarcinoma and poor prognosis.

MUC1 is a highly glycosylated glycoprotein that is often overexpressed in adenocarcinomas. MUC1 has molecular diversity because of a variable number of tandem repeats (from 25-125 repeats) in the extracellular domain of its core protein. MUC1 plays an important role in facilitating invasion and metastasis of malignant cells, and it also inhibits anti-cancer immune activity against malignant cells. We hypothesize that MUC1 allele length polymorphism (variable number of tandem repeats) is associated with development of lung adenocarcinoma. We evaluated MUC1 gene polymorphism using Southern blot analysis of peripheral blood from patients with non-small cell lung cancer (n=56), patients with benign respiratory disease (n=52), and healthy volunteers (n=52). We found that large MUC1 allele length was significantly associated with lung adenocarcinoma but not with squamous cell carcinoma of the lung. Adenocarcinoma patients with a homozygous large MUC1 genotype had a worse prognosis than patients with a heterozygous (large + small) MUC1 genotype or a homozygous small MUC1 genotype. These results suggest that the large MUC1 allele is associated with susceptibility to lung adenocarcinoma and poor prognosis.

Adenocarcinoma↗
PubMed2004

Circulating natural killer T cells in patients with asthma.

Recent studies suggest that therapies targeted at depletion or limiting of natural killer (NK) T cells may be a possible strategy for the treatment of asthma. In the present study, we measured the number of circulating V alpha24+ NKT cells in 32 asthmatic patients and compared these patients with 29 nonatopic healthy controls. We investigated the relationships between NKT cell number and clinical variables such as the number of eosinophils, the circulating level of IgE, and the severity of asthma. In addition, we also investigated the ability of NKT cells to proliferate in response to alpha-galactosyl ceramide (alpha-GalCer) in vitro. The V alpha24+ NKT cell counts of asthmatic patients were significantly lower than those of healthy controls. There were no significant differences observed in asthmatic patients among the subgroups in terms of atopic status and severity. There was no significant correlation between the number of NKT cells and clinical variables. The proliferative response to alpha-GalCer of the patients and controls was not significantly different, indicating no intrinsic proliferative defect of NKT cells in asthma. These results suggest that the number of circulating NKT cells was already decreased in patients with asthma. Further study, such as the evaluation of lung NKT cells, will be needed to determine the role of NKT cells in patients with asthma.

Adult↗