Isao Kobayashi - Academia.edu (original) (raw)

Papers by Isao Kobayashi

Biochemical and biophysical research communications, Jan 17, 2016

Several recent studies have suggested that cancer stem cells (CSCs) are involved in resistance to... more Several recent studies have suggested that cancer stem cells (CSCs) are involved in resistance to gefitinib in non-small cell lung cancer (NSCLC). Oct4, a member of the POU-domain transcription factor family, has been shown to be involved in CSC properties of various cancers. We previously reported that Oct4 and the putative lung CSC marker CD133 were highly expressed in gefitinib-resistant persisters (GRPs) in NSCLC cells, and GRPs exhibited characteristic features of the CSCs phenotype. The aim of this study was to elucidate the role of Oct4 in the resistance to gefitinib in NSCLC cells with an activating epidermal growth factor receptor (EGFR) mutation. NSCLC cell lines, PC9, which express the EGFR exon 19 deletion mutation, were transplanted into NOG mice, and were treated with gefitinib in vivo. After 14-17 days of gefitinib treatment, the tumors still remained; these tumors were referred to as gefitinib-resistant tumors (GRTs). PC9-GRTs showed higher expression of Oct4 and CD1...

European Respiratory Journal, Sep 1, 2014

ABSTRACT [Background] Epithelial-mesenchymal transition (EMT) of alveolar epithelial cells may co... more ABSTRACT [Background] Epithelial-mesenchymal transition (EMT) of alveolar epithelial cells may contribute to the pathogenesis of idiopathic pulmonary fibrosis (IPF). It has been reported that imatinib attenuated bleomycin (BLM)-induced fibrosis in mice. Dasatinib (DAS) is tyrosine kinase inhibitor against platelet derived growth factor receptor as well as imatinib. However, there have been no studies on the effects of DAS on pulmonary fibrosis. [Aim] Our aim is to investigate the effect of DAS on TGFβ-induced EMT in human alveolar epithelial cells in vitro and to evaluate the efficacy of DAS on lung fibrosis in vivo.[Materials and Methods] A549 cells were stimulated with TGFβ and treated with or without DAS. We analyzed epithelial and mesenchymal markers by quantitative real time PCR and western blot and cell motility by wound healing assay. We developed a mouse model for pulmonary fibrosis by intravenous injection of BLM. Either DAS or vehicle was administered by oral gavage, and mice were sacrificed on day 22. We evaluated pathological findings and measured the collagen contents in the lungs of the mice. [Results] In vitro, TGFβ-induced expression of mesenchymal proteins and transcriptional factors were significantly suppressed by the treatment with DAS. Furthermore, DAS markedly inhibited TGFβ-induced cell motility. In vivo, treatment with DAS significantly attenuated BLM-induced lung fibrosis and collagen contents in the lungs. [Conclusion] These findings suggest that DAS inhibits pulmonary fibrosis by suppressing TGFβ-induced EMT. DAS may be a promising and novel anti-fibrotic agent for the prevention of IPF.

Plant and Cell Physiology, Mar 1, 1999

Biochem J, 2000

Exogenous sphingosine 1-phosphate (S1P) increased cytosolic Ca(2+) concentration, stimulated thym... more Exogenous sphingosine 1-phosphate (S1P) increased cytosolic Ca(2+) concentration, stimulated thymidine incorporation (DNA synthesis) and inhibited cell migration in rat aortic smooth-muscle cells (AoSMCs). Although exogenous sphingosine, a substrate of sphingosine kinase or a precursor of S1P, markedly induced the intracellular accumulation of S1P, the lipid failed to mimic the S1P-induced actions. In contrast, dihydrosphingosine 1-phosphate (DHS1P), an S1P receptor agonist, duplicated these S1P actions even though DHS1P was approx. 20-50-fold less potent than S1P. The pharmacological properties of DHS1P for the S1P receptor subtypes Edg-1, Edg-3, Edg-5 and Edg-6 were compared in Chinese hamster ovary (CHO) cells that were overexpressing the respective receptor. In these S1P-receptor-overexpressing cells, DHS1P was approx. 20-30-fold less potent than S1P for the displacement of [(3)H]S1P binding and inositol phosphate response in Edg-5-expressing CHO cells, as was the case for AoSMCs. However, it was slightly (not more than 3-fold) less potent than S1P in cells expressing Edg-1, Edg-3 or Edg-6. Of the above-mentioned four types of S1P receptor, Edg-5 was abundantly expressed in AoSMCs, as demonstrated by Northern blotting. These results suggest that the intracellular accumulation of S1P is not necessary for the S1P-induced Ca(2+) response, for the stimulation of DNA synthesis or for the inhibition of cell migration. Thus these S1P-induced actions might be mediated through extracellular (or cell-surface) S1P receptors in AoSMCs: Edg-5 might be a most important receptor subtype.

European Journal of Pharmacology, Jan 11, 1996

Endocrine Journal, Oct 1, 2009

We performed a receiver operator characteristic (ROC) curve analysis of 3915 men and 2032 women. ... more We performed a receiver operator characteristic (ROC) curve analysis of 3915 men and 2032 women. subjects who were diagnosed with two or more factors among high blood pressure, hyperglycaemia or high triglyceride and/or low HDL were classified as the metabolic syndrome group. By performing a ROC curve analysis, we have determined the cutoff point of waist circumference (WC) and BMI to define metabolic syndrome and further calculated the sensitivity and specificity of these two factors for the diagnosis. Cut-off point for the diagnosis of metabolic syndrome was 85cm (men) and 80cm (women) in WC and 24 (men) and 23 (women) in BMi. By combining these two factors, the sensitivity for the diagnosis increased to more than 80%. We conclude that it is beneficial to combine both WC and BMI for diagnosis of metabolic syndrome.

Journal of Clinical Microbiology, Feb 1, 2000

Acinetobacter baumannii strains resistant to both imipenem (IPM) and ceftazidime (CAZ) were isola... more Acinetobacter baumannii strains resistant to both imipenem (IPM) and ceftazidime (CAZ) were isolated from 1994 through 1996 at Gunma University Hospital. Nine isolates from different inpatients were examined for carbapenem-hydrolyzing activity and for the carbapemase gene bla IMP by the PCR method. All nine isolates were carbapenemase-producing strains that hydrolyzed IPM and that harbored bla IMP . The bla IMP gene was transmissible by conjugation to an IPM-susceptible recipient strain of A. baumannii and conferred resistance to IPM, CAZ, cefotaxime (CTX), ampicillin (AMP), and piperacillin (PIP). Either intermediate or high-level resistance to amikacin (AMK) was transferred from two and five strains, respectively, concomitantly with bla IMP , and gentamicin (GEN) resistance was also transferred in one instance of high-level AMK resistance. Comparative examination of clinical isolates for resistance patterns to nine drugs, IPM, CAZ, CTX, aztreonam, AMP, PIP, AMK, GEN, and norfloxacin, in addition to pulsed-field gel electrophoresis patterns with NotI-digested genomic DNA, confirmed nosocomial transmission of infections involving carbapenemase-producing A. baumannii strains.

Internal Medicine, 2010

The patient was a 69-year-old woman with a family history of type 2 diabetes. Her body mass index... more The patient was a 69-year-old woman with a family history of type 2 diabetes. Her body mass index was 31.5. She was diagnosed as type 2 diabetes 32 years previously, and treated with insulin for 8 years. She had no episode of weight loss. She was hospitalized with diabetic ketoacidosis for the first time. Her GAD antibodies were not detected. However, ICA antibodies and insulin antibodies were positively detected. She was diagnosed with type 1 diabetes. Interestingly, her diabetes state was controlled to the same level after recovery from ketoacidosis.

Endocrinologia japonica, 1977

The effect of chronic administration of sulpiride on serum human growth hormone (hGH), prolactin ... more The effect of chronic administration of sulpiride on serum human growth hormone (hGH), prolactin and thyroid stimulating hormone (TSH) was examined in 6 normal subjects. Sulpiride was given orally at a dose of 300 mg (t.i.d.) for 30 days. Sulpiride raised serum prolactin levels in all subjects examined. In addition, sulpiride suppressed hGH release induced by L-dopa, although the basal hGH level was not changed. Sulpiride treatment appeared to antagonize partially the inhibitory effect of L-dopa on prolactin release. Following thyrotropin-releasing hormone (TRH) injection, the percent increment in prolactin levels from the baseline in sulpiride-treated subjects was less than in controls without sulpiride. In contrast, both the basal and TRH-stimulated TSH levels were not influenced by sulpiride. These observations suggest that sulpiride suppresses L-dopa-induced hGH release and stimulates prolactin release, presumably by acting against the dopaminergic mechanism either on the hypoth...

Heart (British Cardiac Society), 2001

American journal of hypertension, 1999

Hormone replacement therapy (HRT) reduces the incidence of cardiovascular disease (CVD) in postme... more Hormone replacement therapy (HRT) reduces the incidence of cardiovascular disease (CVD) in postmenopausal women (PMW). Recently, it has been reported that HRT declines angiotensin converting enzyme (ACE) activity, which may be one of the factors protecting against CVD. We measured the plasma levels of bradykinin, which would be expected to increase because the bradykinin-degrading enzyme (kinase II) is the same as ACE. Treatment with conjugated estrogens (0.625 mg/day) and medroxyprogesterone (2.5 mg/ day) was given for 3 months as HRT to 19 hypertensive and 19 normotensive PMW. Plasma bradykinin and ACE activity levels were measured at baseline and after 3 months of HRT. The plasma levels of ACE activity in both the hypertensive and normotensive PMW were significantly reduced by HRT. The plasma levels of bradykinin in the hypertensive PMW were significantly increased by HRT, whereas the administration of HRT tended to increase plasma levels of bradykinin in the normotensive PMW. Th...

Research in experimental medicine. Zeitschrift für die gesamte experimentelle Medizin einschliesslich experimenteller Chirurgie, 1998

We evaluated the effects of oral administration of E4021 (100 mg/kg/day), a type V phosphodiester... more We evaluated the effects of oral administration of E4021 (100 mg/kg/day), a type V phosphodiesterase inhibitor, on immunoreactivities of endothelin-1, endothelin receptors, and nitric oxide synthases in pulmonary arteries in a rat model of pulmonary hypertension. Immunoreactivities of endothelin-1 and endothelial nitric oxide synthase were observed significantly less frequently, together with significant reduction of right ventricular overload and medial thickening in rats treated with E4021 than in the control with monocrotaline on day 28. The levels of plasma endothelin-1 and serum nitrite and nitrate were significantly lower in rats that received E4021 than in the control with monocrotaline. Oral administration of E4021 modulates endogenous immunoreactivities of endothelin-1 and endothelial nitric oxide synthase with the improvement or right ventricular overload and medial thickening.

Journal of Diabetes Investigation, 2010

Pregnancy and the postpartum period are associated with changes of the immune system. These chang... more Pregnancy and the postpartum period are associated with changes of the immune system. These changes might eventually result in autoimmune diseases, such as Graves&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; disease and type 1 diabetes mellitus, in the postpartum period. We describe a case of a patient with gestational diabetes who developed both Graves&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; disease and type 1 diabetes mellitus in the postpartum period. The pathology of gestational diabetes (GDM) is close to that of type 2 diabetes mellitus. However, the present case emphasizes the importance of screening and monitoring high-risk GDM patients for all available autoimmune antibodies throughout pregnancy and the postpartum period, as GDM has a risk of developing into type 1 diabetes and multiple autoimmune diseases. In addition, only Graves&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; disease was transient, whereas type 1 diabetes mellitus remained permanent in the present case. Thus, the present case shows etiological differences between these two autoimmune diseases. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2010.00089.x,2011).

[Background] Epithelial-mesenchymal transition (EMT) of alveolar epithelial cells may contribute ... more [Background] Epithelial-mesenchymal transition (EMT) of alveolar epithelial cells may contribute to the pathogenesis of idiopathic pulmonary fibrosis (IPF). It has been reported that imatinib attenuated bleomycin (BLM)-induced fibrosis in mice. Dasatinib (DAS) is tyrosine kinase inhibitor against platelet derived growth factor receptor as well as imatinib. However, there have been no studies on the effects of DAS on pulmonary fibrosis. [Aim] Our aim is to investigate the effect of DAS on TGFβ-induced EMT in human alveolar epithelial cells in vitro and to evaluate the efficacy of DAS on lung fibrosis in vivo.[Materials and Methods] A549 cells were stimulated with TGFβ and treated with or without DAS. We analyzed epithelial and mesenchymal markers by quantitative real time PCR and western blot and cell motility by wound healing assay. We developed a mouse model for pulmonary fibrosis by intravenous injection of BLM. Either DAS or vehicle was administered by oral gavage, and mice were ...

Background and aim: Idiopathic pulmonary fibrosis (IPF) is a chronic pulmonary disorder of unknow... more Background and aim: Idiopathic pulmonary fibrosis (IPF) is a chronic pulmonary disorder of unknown etiology, and is characterized by accumulation of extracellular matrix proteins including collagen in the lungs. Metformin is anti-diabetic agent that improves insulin sensitivity in patients with type II diabetes. It has been recently reported that metformin partially reduced airway inflammation and remodeling, and decreased oxidative stress in a murine model of chronic asthma. However, there has been no study that metformin can inhibit lung fibrosis. Our aim is to investigate the efficacy of metformin on pulmonary fibrosis in vivo. Materials and methods: We developed a mouse model for pulmonary fibrosis by intravenous injection of bleomycin (BLM; 10 mg/kg/day) for consecutive five days. Either metformin (200 mg/kg/day) or vehicle was administered by intraperitoneal injection between day 8 to day 20, and mice were sacrificed on day 22. We evaluated pathological findings and measured t...

Background] Idiopathic pulmonary fibrosis (IPF) is a chronic pulmonary disorder of unknown etiolo... more Background] Idiopathic pulmonary fibrosis (IPF) is a chronic pulmonary disorder of unknown etiology, and is characterized by accumulation of extracellular matrix (ECM) protein such as fibronectin and collagen in the lungs. TGFb-mediated epithelial-mesenchymal transition (EMT) of alveolar epithelial cells may contribute to the pathogenesis of IPF. On the other hand, tranilast, anti-allergic drug, is capable of suppressing TGFb, and is reported to inhibit interstitial renal fibrosis in murine model. [Materials and Methods] We investigated an effect of tranilast on TGFb-induced EMT in A549 human alveolar epithelial cells in vitro. To evaluate the efficacy of tranilast on lung fibrosis in vivo, we developed a mouse model for pulmonary fibrosis by intravenous injection of bleomycin (BLM). Tranilast were administered by oral gavage, and mice were sacrificed on day 22. [Result] Treatment with TGFb induced EMT in A549 cells in vitro, and expression of mesenchymal proteins including fibronec...

[Background] Advanced non-small cell lung cancer (NSCLC) patients with idiopathic pulmonary fibro... more [Background] Advanced non-small cell lung cancer (NSCLC) patients with idiopathic pulmonary fibrosis (IPF), need to be carefully treated with cytotoxic chemotherapy because of high incidence of pulmonary toxicity. Pemetrexed (PEM) is one of the key cytotoxic drugs for advanced NSCLC. However, the safety, particularly the incidence of interstitial lung disease (ILD), and efficacy of PEM in NSCLC patients with IPF are unknown. [Aim] To investigate the safety and efficacy of PEM in NSCLC patients with IPF. [Patients and Method] The medical records of NSCLC patients with or without IPF and treated with PEM monotherapy (500mg/m3, every 3 weeks) were retrospectively reviewed. [Result] 106 NSCLC patients were treated with PEM monotherapy at Juntendo University Hospital between April 2009 and January 2013. Among them, 11 patients were diagnosed as having IPF before treatment (designated as IPF group), and 95 patients were not diagnosed as having IPF before treatment (non-IPF group). 2 patie...