14 results on '"Nakatsumi, Y"'
Search Results
2. Effects of a thromboxane synthetase inhibitor (OKY-046) and a lipoxygenase inhibitor (AA-861) on bronchial responsiveness to acetylcholine in asthmatic subjects.
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Fujimura, M, Sasaki, F, Nakatsumi, Y, Takahashi, Y, Hifumi, S, Taga, K, Mifune, J, Tanaka, T, and Matsuda, T
- Abstract
The effect of a selective thromboxane synthetase inhibitor, OKY-046, and a selective 5-lipoxygenase inhibitor, AA-861, on bronchial responsiveness to acetylcholine was studied in 23 asthmatic subjects. The provocative concentration of acetylcholine producing a 20% fall in forced expiratory volume in one second (PC20 FEV1) was measured before and after oral administration of OKY-046 (3000 mg over four days) and AA-861 (1100 mg over four days) and inhalation of OKY-046 (30 mg) in 10, 10, and nine asthmatic subjects respectively. Baseline values of FEV1 and forced vital capacity (FVC) were not altered by oral OKY-046, oral AA-861, or inhaled OKY-046. The geometric mean value of PC20 FEV1 increased significantly from 0.55 to 2.24 mg/ml after oral OKY-046, but was unchanged after inhalation of OKY-046 and after oral administration of AA-861. These results suggest that thromboxane A2 may play a part in bronchial hyperresponsiveness to acetylcholine. [ABSTRACT FROM PUBLISHER]
- Published
- 1986
3. An effective case of bronchoscopic balloon dilatation for tuberculous bronchial stenosis.
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Ichikawa Y, Kurokawa K, Furusho S, Nakatsumi Y, Yasui M, and Katayama N
- Abstract
Endobronchial tuberculosis often causes bronchial stenosis. Balloon dilation is a minimally invasive and effective bronchoscopic intervention for bronchial stenosis; however, reports on balloon dilation in older individuals are limited. We present a case of a 77-year-old woman with endobronchial tuberculosis and clarify the efficacy and safety of balloon dilation. She presented with dyspnea, right lung atelectasis, and respiratory failure 55 days after initiation of antituberculosis therapy. We performed bronchoscopic balloon dilatation for the right main bronchial stenosis. Consequently, respiratory failure rapidly improved. Chest computed tomography (CT) showed improved lung atelectasis; however, severe bronchial stenosis and rhonchi persisted. Therefore, we performed a second balloon dilatation. CT 3 months after the first balloon dilation showed right upper bronchial stenosis and right lung middle lobe atelectasis. Restenosis was absent 21 months after third balloon dilatation. Bronchoscopic balloon dilation is effective for restenosis with repeated treatment and can be safely performed in older individuals., Competing Interests: None declared., (© 2023 The Authors. Respirology Case Reports published by John Wiley & Sons Australia, Ltd on behalf of The Asian Pacific Society of Respirology.)
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- 2023
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4. Multi-Institutional Prospective Cohort Study of Patients With Pulmonary Hypertension Associated With Respiratory Diseases.
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Tanabe N, Kumamaru H, Tamura Y, Taniguchi H, Emoto N, Yamada Y, Nishiyama O, Tsujino I, Kuraishi H, Nishimura Y, Kimura H, Inoue Y, Morio Y, Nakatsumi Y, Satoh T, Hanaoka M, Kusaka K, Sumitani M, Handa T, Sakao S, Kimura T, Kondoh Y, Nakayama K, Tanaka K, Ohira H, Nishimura M, Miyata H, and Tatsumi K
- Subjects
- Familial Primary Pulmonary Hypertension, Humans, Japan, Prospective Studies, Hypertension, Pulmonary complications, Hypertension, Pulmonary drug therapy, Lung Diseases, Interstitial complications, Lung Diseases, Interstitial drug therapy, Respiration Disorders complications, Respiration Disorders drug therapy
- Abstract
Background: There is limited evidence for pulmonary arterial hypertension (PAH)-targeted therapy in patients with pulmonary hypertension associated with respiratory disease (R-PH). Therefore, we conducted a multicenter prospective study of patients with R-PH to examine real-world characteristics of responders by evaluating demographics, treatment backgrounds, and prognosis., Methods and results: Among the 281 patients with R-PH included in this study, there was a treatment-naïve cohort of 183 patients with normal pulmonary arterial wedge pressure and 1 of 4 major diseases (chronic obstructive pulmonary diseases, interstitial pneumonia [IP], IP with connective tissue disease, or combined pulmonary fibrosis with emphysema); 43% of patients had mild ventilatory impairment (MVI), whereas 52% had a severe form of PH. 68% received PAH-targeted therapies (mainly phosphodiesterase-5 inhibitors). Among patients with MVI, those treated initially (i.e., within 2 months of the first right heart catheterization) had better survival than patients not treated initially (3-year survival 70.6% vs. 34.2%; P=0.01); there was no significant difference in survival in the group with severe ventilatory impairment (49.6% vs. 32.1%; P=0.38). Responders to PAH-targeted therapy were more prevalent in the group with MVI., Conclusions: This first Japanese registry of R-PH showed that a high proportion of patients with MVI (PAH phenotype) had better survival if they received initial treatment with PAH-targeted therapies. Responders were predominant in the group with MVI.
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- 2021
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5. Different prognosis between severe and very severe obstructive sleep apnea patients; Five year outcomes.
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Hamaoka T, Murai H, Takata S, Hirai T, Sugimoto H, Mukai Y, Okabe Y, Tokuhisa H, Takashima SI, Usui S, Sakata K, Kawashiri MA, Sugiyama Y, Nakatsumi Y, and Takamura M
- Subjects
- Adult, Aged, Coronary Artery Disease mortality, Female, Heart Failure mortality, Hospitalization, Humans, Male, Middle Aged, Prognosis, Proportional Hazards Models, Severity of Illness Index, Sleep Apnea, Obstructive mortality, Stroke mortality, Continuous Positive Airway Pressure, Sleep Apnea, Obstructive therapy
- Abstract
Background: Obstructive sleep apnea (OSA) is characterized by augmented sympathetic nerve activity. In our previous study, patients with OSA and an apnea-hyperpnea index (AHI)>55events/h showed increased single-unit muscle sympathetic nerve activity compared to patients with OSA and AHI of 30-55events/h. However, the prognostic impact in these patients remains unclear., Methods: Ninety-one OSA patients were included. All patients who had indication for continuous positive airway pressure (CPAP) were treated with CPAP. Patients were divided into three groups: mild/moderate OSA (S), AHI<30events/h (n=44); severe OSA (SS), AHI 30-55events/h (n=29); and very severe OSA (VSS), AHI>55events/h (n=18). The primary endpoint was a composite outcome composed of death, cardiovascular events, stroke, and heart failure with hospitalization., Results: In the 5-year follow-up, the primary event rate in the SS group [3 events (7%)] was the same as that in the S group [3 events (10%)]. However, the VSS group showed a significantly higher primary event rate among the three groups [6 events (33%), p<0.05]. In Cox regression analysis, the VSS group had the highest hazard ratio compared to other risk factors., Conclusions: CPAP was effective for preventing cardiovascular disease in patients with severe OSA, however patients with very severe OSA still had a high event rate, indicating that CPAP treatment might be insufficient to reduce the OSA-related risk burden in patients with very severe OSA. Additional systemic medical treatment for CPAP might be needed in patients with very severe OSA., (Copyright © 2020. Published by Elsevier Ltd.)
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- 2020
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6. Severity Indices for Obstructive Sleep Apnea Syndrome Reflecting Glycemic Control or Insulin Resistance.
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Isobe Y, Nakatsumi Y, Sugiyama Y, Hamaoka T, Murai H, Takamura M, Kaneko S, Takata S, and Takamura T
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- Aged, Female, Humans, Male, Middle Aged, Oxygen blood, Severity of Illness Index, Sympathetic Nervous System physiology, Continuous Positive Airway Pressure methods, Glycated Hemoglobin physiology, Insulin Resistance physiology, Sleep Apnea, Obstructive physiopathology
- Abstract
Objective We aimed to identify obstructive sleep apnea syndrome (OSAS) severity indices reflecting the anthropometric and metabolic characteristics of patients with OSAS. Methods A total of 76 patients with OSAS underwent nasal continuous positive airway pressure (nCPAP). We also investigated the effects of nCPAP on OSAS-associated muscle sympathetic nerve activity (MSNA), risk for cardiovascular diseases, and insulin secretion and sensitivity. Results Among the OSAS severity indices, HbA1c was significantly correlated with the apnea-hypopnea index, whereas HOMA-beta, HOMA-IR, and hepatic insulin resistance were significantly correlated with % SpO
2 <90%, independent of age, gender, and body mass index (BMI). Burst incidence of MSNA was independently associated with only a 3% oxygen desaturation index. nCPAP therapy significantly lowered the OSAS severity indices and reduced the burst rate, burst incidence, and heart rate. Conclusion The OSAS severity indices reflecting apnea/hypopnea are associated with glycemic control, whereas those reflecting hypoxia, particularly % SpO2 <90%, are associated with hepatic insulin resistance independent of obesity. Both types of OSAS severity indices, especially the 3% oxygen desaturation index (reflecting intermittent hypoxia), are independently associated with MSNA, which is dramatically lowered with the use of nCPAP therapy. These findings may aid in interpreting each OSAS severity index and understanding the pathophysiology of OSAS in clinical settings.- Published
- 2019
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7. Significant Association Between Coronary Artery Low-Attenuation Plaque Volume and Apnea-Hypopnea Index, But Not Muscle Sympathetic Nerve Activity, in Patients With Obstructive Sleep Apnea Syndrome.
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Hamaoka T, Murai H, Kaneko S, Usui S, Inoue O, Sugimoto H, Mukai Y, Okabe Y, Tokuhisa H, Takashima S, Kato T, Furusho H, Kashiwaya S, Sugiyama Y, Nakatsumi Y, Takata S, and Takamura M
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- Aged, Female, Humans, Male, Middle Aged, Coronary Angiography, Coronary Artery Disease diagnostic imaging, Coronary Artery Disease physiopathology, Plaque, Atherosclerotic diagnostic imaging, Plaque, Atherosclerotic physiopathology, Polysomnography, Sleep Apnea, Obstructive diagnostic imaging, Sleep Apnea, Obstructive physiopathology, Sympathetic Nervous System diagnostic imaging, Sympathetic Nervous System physiopathology, Tomography, X-Ray Computed
- Abstract
Background: Obstructive sleep apnea syndrome (OSAS) is associated with augmented sympathetic nerve activity and cardiovascular diseases. However, the interaction between coronary artery plaque characteristics and sympathetic nerve activity remains unclear. The purpose of this study was to clarify the relationships between coronary artery plaque characteristics, sleep parameters and single- and multi-unit muscle sympathetic nerve activity (MSNA) in OSAS patients. Methods and Results: A total of 32 OSAS patients who underwent full-polysomnography participated in this study. The coronary plaque volume was calculated with 320-slice coronary computed tomography (CT). Single- and multi-unit MSNA were obtained during the daytime within 1 week from full-polysomnography. Patients were divided into 2 groups according to their apnea-hypopnea index (AHI) score (mild-moderate group, AHI <30; and severe group, AHI ≥30). There were no group differences in risk factors for atherosclerosis; however, severe AHI patients showed significantly high single-unit MSNA, and low- and intermediate-attenuation plaque volumes. In regression analysis, the plaque volume of any CT value was not associated with single- or multi-unit MSNA; only AHI significantly correlated with low-attenuation plaque volume (R=0.52, P<0.05)., Conclusions: Our findings provided the evidence that AHI is an independent predictor for low-attenuated, vulnerable plaque volume, but not daytime MSNA, in patients with OSAS.
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- 2018
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8. Single-Unit Muscle Sympathetic Nerve Activity Reflects Sleep Apnea Severity, Especially in Severe Obstructive Sleep Apnea Patients.
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Hamaoka T, Murai H, Kaneko S, Usui S, Okabe Y, Tokuhisa H, Kato T, Furusho H, Sugiyama Y, Nakatsumi Y, Takata S, and Takamura M
- Abstract
Obstructive sleep apnea syndrome (OSAS) is associated with augmented sympathetic nerve activity, as assessed by multi-unit muscle sympathetic nerve activity (MSNA). However, it is still unclear whether single-unit MSNA is a better reflection of sleep apnea severity according to the apnea-hypopnea index (AHI). One hundred and two OSAS patients underwent full polysomnography and single- and multi-unit MSNA measurements. Univariate and multivariate regression analysis were performed to determine which parameters correlated with OSAS severity, which was defined by the AHI. Single- and multi-unit MSNA were significantly and positively correlated with AHI severity. The AHI was also significantly correlated with multi-unit MSNA burst frequency (r = 0.437, p < 0.0001) and single-unit MSNA spike frequency (r = 0.632, p < 0.0001). Multivariable analysis revealed that SF was correlated most significantly with AHI (T = 7.27, p < 0.0001). The distributions of multiple single-unit spikes per one cardiac interval did not differ between patients with an AHI of <30 and those with and AHI of 30-55 events/h; however, the pattern of each multiple spike firing were significantly higher in patients with an AHI of >55. These results suggest that sympathetic nerve activity is associated with sleep apnea severity. In addition, single-unit MSNA is a more accurate reflection of sleep apnea severity with alternation of the firing pattern, especially in patients with very severe OSAS.
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- 2016
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9. Plasma levels of platelet-derived microparticles in patients with obstructive sleep apnea syndrome.
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Maruyama K, Morishita E, Sekiya A, Omote M, Kadono T, Asakura H, Hashimoto M, Kobayashi M, Nakatsumi Y, Takada S, and Ohtake S
- Subjects
- Blood Platelets metabolism, Case-Control Studies, Cell-Derived Microparticles metabolism, Female, Fibrin metabolism, Humans, Male, Middle Aged, Plasminogen Activator Inhibitor 1 blood, Platelet Activation, Polysomnography, Prognosis, Sleep Apnea, Obstructive blood, Blood Platelets pathology, Cell-Derived Microparticles pathology, Sleep Apnea, Obstructive diagnosis
- Abstract
Aim: Obstructive sleep apnea syndrome (OSAS) has been associated with high cardiovascular morbidity and mortality, and patients suffer from repeated episodes of hypoxia. Platelet-derived microparticles (PDMPs) are released via platelet activation by various agonists, including inflammatory cytokines or high shear stress. Plasminogen activator inhibitor -1 (PAI-1) is a fibrinolytic marker and soluble fibrin (SF) is a coagulation activation marker. We examined plasma levels of PDMPs, PAI-1 and SF in patients with OSAS. We also examined the effects of continuous positive airway pressure (CPAP) on plasma levels of PDMPs., Methods: Full polysomnography (PSG) monitoring was performed on 27 patients. The apneahypopnea index (AHI) of 5 events/h or less than 30 events/h indicated mild to moderate OSAS, and an AHI of 30 events/h or more indicated severe OSAS. Plasma levels of PDMPs were measured using an ELISA kit, and PAI and SF were determined by a latex immunoassay. In addition, the effects of CPAP treatment were studied in 7 patients., Result: The plasma level of PDMPs was significantly higher in patients with severe OSAS (15.8±10.4 U/mL) than normal controls (10.8±7.1 U/mL, p < 0.05) and patients with mild to moderate OSAS (9.2±3.5 U/mL, p < 0.05). The plasma levels of PDMPs correlated with the AHI (r = 0.39, p < 0.05). In addition, CPAP treatment decreased the plasma level of PDMPs (11.9±5.6 U/mL to 6.7±3.2 U/mL, p < 0.05)., Conclusions: Patients with OSAS might be at increased cardiovascular risk due to elevated PDMPs. Moreover a decrease in the plasma level of PDMPs by treatment with CPAP might reduce cardiovascular risk.
- Published
- 2012
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10. Antitussive effects of the leukotriene receptor antagonist montelukast in patients with cough variant asthma and atopic cough.
- Author
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Kita T, Fujimura M, Ogawa H, Nakatsumi Y, Nomura S, Ishiura Y, Myou S, and Nakao S
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- Acetates adverse effects, Adult, Aged, Antitussive Agents adverse effects, Asthma immunology, Asthma physiopathology, Clenbuterol adverse effects, Cough, Cyclopropanes, Drug Therapy, Combination, Female, Humans, Leukotriene Antagonists adverse effects, Male, Middle Aged, Quinolines adverse effects, Respiratory Function Tests, Sulfides, Treatment Outcome, Acetates administration & dosage, Antitussive Agents administration & dosage, Asthma drug therapy, Clenbuterol administration & dosage, Leukotriene Antagonists administration & dosage, Quinolines administration & dosage
- Abstract
Background: Chronic cough is the only symptom of cough variant asthma (CVA) and atopic cough (AC). Cysteinyl leukotriene receptor antagonists have been shown to be effective in CVA, but there are no reports on their effectiveness in AC. To evaluate the antitussive effect of montelukast, a leukotriene receptor antagonist, in CVA and AC., Methods: Seventy-five patients with chronic cough received diagnostic bronchodilator therapy with oral clenbuterol hydrochloride for 6 days. Of the 75 patients, 48 and 27 met the simplified diagnostic criteria for CVA and AC, respectively. Patients with CVA were randomly divided into 3 groups: montelukast, clenbuterol, and montelukast plus clenbuterol. Patients with AC were randomly divided into 2 groups: montelukast and placebo. The efficacy of cough treatment was assessed with a subjective cough symptom scale (0 meant "no cough" and 10 denoted "cough as bad as at first visit"). The cough scale, pulmonary function test, and peak expiratory flow rate (PEF) were evaluated before and after 2 weeks of treatment., Results: In patients with CVA, 2-week treatment with montelukast, clenbuterol, and montelukast plus clenbuterol all significantly decreased cough scores and treatment with montelukast plus clenbuterol was superior to treatment with montelukast alone. In the montelukast plus clenbuterol group, PEF values in the morning and evening significantly increased after 2 weeks compared with values before treatment. In patients with AC, scores on the cough scale did not differ significantly between the montelukast group and the placebo group., Conclusions: Montelukast was confirmed to suppress chronic non-productive cough in CVA, whereas it was not effective in non-productive cough in AC.
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- 2010
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11. Eosinophilic pneumonia (EP) associated with rheumatoid arthritis in which drug-induced eosinophilic pneumonia could be ruled out.
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Tambo Y, Fujimura M, Yasui M, Kasahara K, Nakatsumi Y, and Nakao S
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- Aged, Anti-Inflammatory Agents, Non-Steroidal therapeutic use, Antirheumatic Agents therapeutic use, Arthritis, Rheumatoid drug therapy, Cysteine analogs & derivatives, Cysteine therapeutic use, Diagnosis, Differential, Glucocorticoids adverse effects, Glucocorticoids therapeutic use, Humans, Male, Methotrexate therapeutic use, Prednisolone adverse effects, Prednisolone therapeutic use, Pulmonary Eosinophilia chemically induced, Arthritis, Rheumatoid complications, Pulmonary Eosinophilia diagnosis, Pulmonary Eosinophilia etiology
- Abstract
A 72 year-old man. He was diagnosed with rheumatoid arthritis in 2002. In January 2005 he noted productive cough and fever; he was diagnosed as eosinophilic pneumonia (EP). We discontinued administration of bucillamine and methotrexate and started to treat with oral prednisolone 30 mg daily. To rule out drug-induced EP, prednisolone was tapered by 10 mg per week. Consolidation occurred in the right lower lobe when prednisolone was decreased to 5 mg daily. After increasing the dose of prednisolone to 30 mg daily again, consolidation was promptly resolved. It was considered to be important to rule out drug-induced EP.
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- 2008
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12. Randomized phase II trial of OK-432 in patients with malignant pleural effusion due to non-small cell lung cancer.
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Kasahara K, Shibata K, Shintani H, Iwasa K, Sone T, Kimura H, Nobata K, Hirose T, Yoshimi Y, Katayama N, Ishiura Y, Kita T, Nishi K, Nakatsumi Y, Ryoma Y, Fujimura M, and Nakao S
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- Aged, Aged, 80 and over, Antineoplastic Agents adverse effects, Carcinoma, Non-Small-Cell Lung pathology, Dose-Response Relationship, Drug, Drainage methods, Female, Humans, Lung Neoplasms pathology, Male, Middle Aged, Picibanil adverse effects, Pleural Effusion, Malignant pathology, Pleural Effusion, Malignant therapy, Antineoplastic Agents therapeutic use, Carcinoma, Non-Small-Cell Lung drug therapy, Lung Neoplasms drug therapy, Picibanil therapeutic use, Pleural Effusion, Malignant drug therapy
- Abstract
To determine the optimum dose of OK-432 for intrathoracic administration, a multicenter randomized phase II trial was conducted in patients with malignant pleural effusion due to non-small cell lung cancer. Patients with histologically- or cytologically-proven malignant pleural effusions were randomized to arm A (10 Klinische Einheit (KE) of OK-432) or arm B (1 KE of OK-432). OK-432 was injected intrapleurally over 30 min on days 1 and 3 and the chest tube was clamped for 6 h. If control was inadequate on day 8, 10 KE was administered on days 8 and 10 in each treatment arm. Forty patients were enrolled and 38 patients were eligible (19 in arm A and 19 in arm B). The effusion control rate on day 8 was 79% in arm A and 53% in arm B, while control rates on day 28 were 74% and 84%, respectively. The median drainage time after administration was significantly shorter in arm A (4.0 +/- 1.2 days) than in arm B (7.0 +/- 1.7 days). The total drainage volume was also significantly less in arm A than in arm B. No grade 4 toxicities or treatment-related deaths were observed in either treatment arm. Intrathoracic injection of OK-432 is a feasible treatment for malignant pleural effusion. Although the malignant pleural effusion control rate was equivalent in each treatment arm, faster control and less drainage were achieved in arm A. A dose of OK-432 10 KE/body is, therefore, recommended for further trial.
- Published
- 2006
13. EGFR mutation of tumor and serum in gefitinib-treated patients with chemotherapy-naive non-small cell lung cancer.
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Kimura H, Kasahara K, Shibata K, Sone T, Yoshimoto A, Kita T, Ichikawa Y, Waseda Y, Watanabe K, Shiarasaki H, Ishiura Y, Mizuguchi M, Nakatsumi Y, Kashii T, Kobayashi M, Kunitoh H, Tamura T, Nishio K, Fujimura M, and Nakao S
- Subjects
- Adenocarcinoma drug therapy, Adenocarcinoma genetics, Adult, Aged, Aged, 80 and over, Antineoplastic Agents adverse effects, Carcinoma, Large Cell drug therapy, Carcinoma, Large Cell genetics, Carcinoma, Non-Small-Cell Lung genetics, Carcinoma, Squamous Cell drug therapy, Carcinoma, Squamous Cell genetics, Exons, Female, Gefitinib, Humans, Kaplan-Meier Estimate, Lung Neoplasms genetics, Male, Middle Aged, Mutation, Polymerase Chain Reaction, Quinazolines adverse effects, Antineoplastic Agents therapeutic use, Biomarkers, Tumor blood, Carcinoma, Non-Small-Cell Lung drug therapy, DNA blood, ErbB Receptors genetics, Lung Neoplasms drug therapy, Quinazolines therapeutic use
- Abstract
Background: The authors evaluate the efficacy and safety of gefitinib monotherapy in chemotherapy-naive patients with advanced non-small-cell lung cancer (NSCLC). A secondary endpoint is to evaluate the relationship between clinical manifestations and epidermal growth factor receptor (EGFR) mutation status., Methods: Japanese chemotherapy-naive NSCLC patients were enrolled. They had measurable lesions, Eastern Cooperative Oncology Group performance status of 0 to 2, and adequate organ and bone marrow function. Patients received 250 mg of oral gefitinib daily. EGFR mutations in exon 18, 19, and 21 of DNA extracted from tumor and serum were analyzed by genomic polymerase chain reaction and direct sequence., Results: All 30 patients were eligible for the assessment of efficacy and safety. An objective response and stable disease were observed in 10 patients (33.3%) and nine patients (30.0%), respectively. The median time to progression was 3.3 months and the median overall survival was 10.6 months. The 1-year survival rate was 43.3%. Grade 3 toxicities were observed in seven patients. EGFR mutation was observed in four of 13 (30.8%) tumors, and two of them achieved partial response. In serum samples, three of 10 patients with EGFR mutations in the serum before treatment had a response to gefitinib. EGFR mutation was observed in 10 of 27 and significantly more frequently observed in the posttreatment samples from patients with a partial response or stable disease than in those from patients with progressive disease (p = 0.006)., Conclusions: Gefitinib monotherapy in chemotherapy-naive NSCLC patients was active, with acceptable toxicities. These results warrant further evaluation of gefitinib monotherapy as a first-line therapy. The EGFR mutation in serum DNA may be a biomarker for monitoring the response to gefitinib during treatment.
- Published
- 2006
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14. Establishment and characterization of non-small cell lung cancer cell lines resistant to mitomycin C under aerobic conditions.
- Author
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Shibata K, Kasahara K, Bando T, Nakatsumi Y, Fujimura M, Tsuruo T, and Matsuda T
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- Aerobiosis, Antineoplastic Agents pharmacokinetics, Carcinoma, Non-Small-Cell Lung metabolism, Dihydrolipoamide Dehydrogenase metabolism, Drug Screening Assays, Antitumor, Humans, Lung Neoplasms metabolism, Tumor Cells, Cultured, Antineoplastic Agents pharmacology, Carcinoma, Non-Small-Cell Lung pathology, Drug Resistance, Multiple physiology, Lung Neoplasms pathology, Mitomycin pharmacology
- Abstract
To elucidate the mechanisms of acquired resistance to mitomycin C (MMC) in non-small cell lung cancer (NSCLC), we established two MMC-resistant NSCLC sublines by continuous exposure to MMC, using PC-9 as a parent cell line. The sublines, PC-9/MC2 and PC-9/MC4, were 6.4- and 10-fold more resistant to MMC than their parent cell line, respectively, at the IC50 value as determined by MTT assay. They exhibited cross-resistance to EO9, but were not resistant to cisplatin, vindesine, etoposide, carboquone, or KW-2149, a novel MMC derivative. They were collaterally sensitive to adriamycin and menadione. Accumulation of the drug was decreased in the resistant sublines to about 60% of that in the parent cells. Cytosolic DT-diaphorase (DTD) activities were decreased to 13.5 +/- 3.2 in PC9/MC2 and 1.3 +/- 0.6 in PC-9/MC4 from 261.5 +/- 92.7 nmol/min/mg protein in the parent PC-9. NADH:cytochrome b5 reductase activities in both of the resistant cell lines were significantly decreased as compared to that in the parent cell line. Addition of dicumarol resulted in a two-fold increase in IC50 value in PC-9, whereas the IC50 value showed no change in PC-9/MC4. Moreover, dicumarol did not affect the sensitivities to KW-2149 but decreased the sensitivities to EO9 in both the parent and the resistant cell lines. Formation of an alkylating metabolite was significantly decreased in the resistant cells, in parallel to the degree of resistance. We concluded that deficient drug activation due to decreased DTD activity was important as a mechanism of resistance to MMC in PC-9, a relatively DTD-rich NSCLC cell line.
- Published
- 1995
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