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Masao Yamaguchi

Publications and source records attributed to Masao Yamaguchi.

24 records · Page 2Linked to original sources
PubMed2003

[A case of eosinophilic lung disease presenting asthma-like symptoms and centrilobular shadows in both lung fields].

This case, in a 23-year-old man presenting with cough, sputum, dyspnea on effort and wheezing, had been diagnosed as bronchial asthma at another hospital. Because inhaled steroid and theophylline were far from effective, he was admitted to our hospital for further evaluation. A blood test revealed marked eosinophilia. Chest radiography showed diffuse, small nodular shadows in both lung fields, and a chest CT scan demonstrated diffuse centrilobular nodules and thickening of the bronchi and bronchioles. A spirometric test showed obstructive and restrictive ventilatory impairment, but the depressed forced vital capacity failed to show improvement in response to bronchodilator inhalation, discouraging a diagnosis of asthma. Eosinophilic lung disease with prominent eosinophilic bronchiolitis was diagnosed on the basis of BAL eosinophilia and thoracoscopic lung biopsy findings. The symptoms and blood eosinophilia were responsive to administration of oral prednisolone (30 mg daily); radiographic and CT findings also showed improvement. This case showed a marked similarity to the recently reported "eosinophilic bronchiolitis", and was probably not a type of bronchial asthma.

Administration, Oral↗
PubMed2002

Activation markers of human basophils: CD69 expression is strongly and preferentially induced by IL-3.

BACKGROUND: The biological functions of basophils are precisely regulated by various cytokines in vitro, but little is known about surface markers that are upregulated during the cytokine-mediated activation process. OBJECTIVE: It has been well established that CD69, CD44, and CD54 represent "activation markers" for cytokine-mediated eosinophil activation. The objective of this study was to elucidate the expression and regulation of these molecules in human basophils in vitro as well as in vivo. METHODS: Basophils were purified from venous blood by means of density gradient centrifugation followed by negative selection. Surface expression was analyzed by means of flow cytometry. We also studied the expression of CD69, CD44, and CD54 on basophils in bronchoalveolar lavage fluid and blood specimens from patients with asthma. RESULTS: CD44 and CD54 were constitutively expressed on basophils and moderately upregulated by IL-3. On the other hand, CD69 expression was only weakly observed in freshly isolated basophils, but IL-3 induced extremely high levels of expression. Surface CD69 appeared rather slowly in comparison with CD63 and CD11b, and the induction of expression was completed within 24 hours. Basophil CD69 had no functional relevance, but it did have biological relevance. Whole blood basophils from asthmatic individuals expressed significantly higher levels of CD69 than did those from normal individuals. Furthermore, bronchoalveolar lavage fluid basophils showed higher levels of CD69 expression than did blood basophils from the same donors. CONCLUSION: CD69 expression on basophils was preferentially and strongly upregulated by IL-3. CD69 on basophils might be useful as an in vitro as well as in vivo marker of activation of these cells by IL-3.

Aged↗
PubMed2002

A functional study on CysLT(1) receptors in human eosinophils.

BACKGROUND: The cysteinyl leukotrienes (CysLTs) mediate their biological actions through two receptors: CysLT(1) receptor and CysLT(2) receptor. OBJECTIVE: This study was undertaken to examine the direct effects of CysLTs on eosinophils, such as chemotaxis and degranulation, focusing on CysLT(1). METHODS: Eosinophils were isolated from venous blood from normal volunteers who had no history of allergy (purity >99%). They were subjected to reverse transcription-PCR analysis and flow-cytometric analysis for CysLT(1). Binding assays were performed with [(3)H]LTD(4). Purified eosinophils loaded with Fura-2 acetoxymethyl ester were stimulated with CysLTs, and Ca(2+) influx was measured. Eosinophil migration in response to CysLTs was measured using a 96-well multiwell Boyden chamber. Eosinophils were treated with LTD(4) at 10(-6) M for 60 min followed by incubation for 4 h at 37 degrees C in the presence or absence of IL-5 and eosinophil-derived neurotoxin (EDN) release was evaluated. RESULTS: The expression of the mRNA and protein of CysLT(1) on eosinophils and [(3)H]LTD(4)-specific binding to eosinophils were observed. Neither Th1 cytokine (IFN-gamma) nor Th2 cytokines (IL-4 or IL-5) affected CysLT(1) expression in eosinophils. CysLTs induced an increase in intracellular free Ca(2+) in eosinophils via CysLT(1), as suggested by the efficient inhibition by a CysLT(1) antagonist, pranlukast, in addition to the rank order of potency being LTD(4), LTC(4) and LTE(4). LTD(4) stimulated eosinophils to migrate at 10(-6) M via CysLT(1). LTE(4) also induced significant eosinophil migration at 10(-6) M. LTD(4) enhanced EDN release induced by IL-5 via CysLT(1). CONCLUSION: CysLTs induce migration and enhance degranulation in eosinophils via CysLT(1). Accordingly, interaction of CysLTs and CysLT(1) on eosinophils has the potential to play a prominent role in the pathophysiology of asthma.

Calcium↗
PubMed2002

Cytokine-mediated regulation of CXCR4 expression in human neutrophils.

Several lines of evidence have suggested that a CXC chemokine receptor 4 (CXCR4)/stromal cell-derived factor-1 [SDF-1; CXC chemokine ligand 12 (CXCL12)] pair is involved in baseline trafficking of leukocytes into extravascular tissues and that modulation of surface CXCR4 expression may represent an alternative mechanism for control of cell-specific biological responses to SDF-1/CXCL12. We explored the regulation of CXCR4 expression by cytokines in polymorphonuclear neutrophils (PMNs). No significant surface expression of CXCR4 in freshly isolated PMNs was detected, but expression became apparent gradually during incubation. SDF-1alpha/CXCL12 initiated Ca2+ mobilization and migratory responses in 20 h cultured PMNs. The surface CXCR4 expression was suppressed most potently by interferon-gamma (IFN-gamma). IFN-alpha, granulocyte-macrophage colony-stimulating factor (GM-CSF), and G-CSF also inhibited spontaneous CXCR4 expression. Real-time, quantitative PCR experiments revealed that a spontaneous increase and an IFN-gamma-mediated decrease in surface CXCR4 paralleled changes in the CXCR4 mRNA level. These results on PMNs support the argument that the SDF-1 (CXCL12)/CXCR4 system is regulated by cell type-specific mechanisms.

Cytokines↗
PubMed2002

[Acute exacerbation of interstitial pneumonia associated with active systemic lupus erythematosus in a patient with rheumatoid arthritis].

A 36-year-old woman with rheumatoid arthritis was admitted to our hospital for evaluation of newly developed active systemic lupus erythematosus (SLE). After hospitalization, she showed progressive respiratory failure. Chest CT revealed exacerbation of interstitial pneumonia, showing acute development of air-space consolidation and ground-glass opacity in addition to intensified reticular shadows. Administration of high-dose corticosteroids and cyclosporine A resulted in recovery from respiratory failure, accompanied by obvious improvement in the chest radiographs and CT, as demonstrated by the disappearance of air-space consolidation and ground-glass opacity. Clinically, the exacerbation of her interstitial pneumonia was compatible with acute lupus pneumonitis, a rare complication with active SLE.

Acute Disease↗