[Show abstract][Hide abstract] ABSTRACT: Background: Oxygen is important for common eukaryotic cells to generate ATP. Such pathophysiological conditions as ischemic diseases cause tissue hypoxia. In addition, oxygen availability in deep tissues is supposed to be far lower than surrounding atmosphere even in healthy animals, and the oxygen partial pressures in most of the normal tissues are estimated to be around 40-50 mmHg, mild hypoxia so called. Recent studies have demonstrated that the mild hypoxia has distinct effects on living cells from severe hypoxia. For instance, the mild hypoxia was reported to promote cell reprogramming. Although severe hypoxia is known to inhibit cell proliferation, the mild hypoxia has been paradoxically demonstrated to increase cell proliferation. However, it has not been clarified by which molecular mechanisms the mild hypoxia evokes the discontinuous increment of cell proliferation.
Methods: We established the experimental conditions showing the opposite influences of the mild and severe hypoxia on the cell proliferation using undifferentiated Caco2 human colon carcinoma cells in order to clarify the underlying molecular mechanism.
Results: Basal activity of Erk, which is a typical mediator of mitogenic signals, is spontaneously increased specifically in the cells exposed to mild hypoxia, and inhibition of MEK, an upstream kinase of the Erk, completely inhibited the mild hypoxia-induced enhancement of cell proliferation.
Conclusions: The spontaneous hyper-activation of MEK-Erk pathway by mild hypoxia should be the plausible molecular mechanism of the paradoxical promotion of cell proliferation.
General Significance: Our findings will provide clues to molecular basis of mild hypoxia-evoked phenomena such as cell reprogramming.
Biochimica et Biophysica Acta (BBA) - General Subjects 04/2015; 1850(4). DOI:10.1016/j.bbagen.2014.12.006 · 4.38 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background
Peripheral neuropathy is a well-known side effect of vincristine (VCR), a microtubule inhibitor used for R-CHOP or R-CHOP-like (namely R-CVP and R-THP-COP) regimens. Previous studies have shown that both the total dose of VCR and the number of treatment cycles are related to the incidence of VCR-induced peripheral neuropathy (VIPN). However, VIPN will also occur during the first treatment cycle regardless of the total dose of VCR or number of treatment cycles (early-onset VIPN). There is little information about early-onset VIPN, and it is difficult to predict. The present study’s goal was to identify risk factors for early-onset VIPN.
We analyzed the case records of patients who had their first administration of an R-CHOP or R-CHOP-like regimen between April 2008 and August 2013 at Tokushima University Hospital in Tokushima, Japan. To identify the risk factors for early-onset VIPN, we performed univariate and multivariate logistic regression analyses.
Forty-one patients underwent an R-CHOP or R-CHOP-like regimen for the first time at Tokushima University Hospital between April 2008 and August 2013, and 14 patients had grade 1 or higher early-onset VIPN. A univariate analysis revealed that age, the dose of VCR and the concomitant use of aprepitant appeared to be the risk factors of early-onset VIPN. In our calculation using receiver-operator characteristics curves, the cut-off value for patient age was 65 years and that of the dose of VCR was 1.9 mg. A multivariate analysis revealed that VCR dose ≥ 1.9 mg and the concomitant use of the antiemetic aprepitant were independent risk factors for early-onset VIPN.
Our present study showed that the patients who had VCR dose ≥ 1.9 mg and the concomitant use of aprepitant had the risk for early-onset VIPN. This suggests that it is important to use aprepitant in light of the risk of early-onset VIPN and the benefit of aprepitant’s antiemetic effect in R-CHOP and R-CHOP-like regimens.
Journal of Clinical Medicine Research 08/2014; 6(4):252-60. DOI:10.14740/jocmr1856w
[Show abstract][Hide abstract] ABSTRACT: Clinical trials leading to regulatory approval, or registration trials, play a central role in the development of drugs and medical devices. The contribution of support staff, such as the clinical research coordinator (CRC) and administrative officers, in registration trials is now widely recognized. Attending to serious adverse events is an important duty of the CRC and investigators alike, and managing these complications and compensation constitutes a key responsibility. We retrospectively examined the frequency of serious adverse events and compensation events reported from 2007 through 2011 at Tokushima University Hospital, an academic hospital in rural Japan. We present herein the results of our analysis.
Over the five-year period, 284 subjects participating in 106 registration trials experienced a total of 43 serious adverse events, and eight compensation events were documented. Among the serious adverse events, 35 (81.4%) were considered not related to the investigational drug, and 17 (39.5%) resulted in withdrawal of the study drug. Patients with malignant diseases experienced serious adverse events significantly more frequently compared to those with non-malignant diseases (28.3% versus 8.2%, respectively; P < 0.01).
The CRC should be vigilant for serious adverse events in oncology clinical trials due to the generally higher frequency of these complications in subjects with malignancy. However, on an individual basis, the CRC may be seldom involved in the process for compensating serious adverse events. Therefore, the CRC's ability to share such experiences may serve as an opportunity for educating clinical trial support staff at the study site as well as those at other sites. However, further study is warranted to determine the role of the clinical trial support staff in optimizing methods for managing adverse events requiring compensation in registration trials.
BMC Research Notes 04/2014; 7(1):245. DOI:10.1186/1756-0500-7-245
[Show abstract][Hide abstract] ABSTRACT: This study evaluated the combined use of adenosine triphosphate (ATP) bioluminescence and microbiological assays for monitoring environmental surfaces in a teaching hospital to develop a method for rapid detection of microbial contamination that could constitute a health risk to patients. ATP bioluminescence assay and microbiological screening were performed of various surfaces of toilet facilities in outpatient wards. In each of the five sites screened, the ATP levels were significantly higher than on a cleaned, disinfected stainless steel surface, indicating that all screened surfaces were “high-touch” surfaces and the surfaces harbored significantly higher levels of certain organic matter. The microbiological assay confirmed that the microbiological contamination had spread throughout the screened sites. The ATP values of the samples positive for microbes occurred in a significantly higher range than those of the samples negative for microbes (p<0.01). However, no linear relationship was established between the ATP values and aerobic colony counts of the screened sites. These results clearly imply that the use of ATP bioluminescence to measure the microbial contamination of an environment yields qualitative rather than quantitative data. In conclusion, ATP monitoring is a rapid and convenient method to assess environmental contamination and persistence of microbes and to monitor the effectiveness of current cleaning practices.
Japanese Journal of Environmental Infections 01/2014; 29(6):417-423. DOI:10.4058/jsei.29.417
[Show abstract][Hide abstract] ABSTRACT: Denosumab, a fully human monoclonal antibody that inhibits the receptor activator of nuclear factor-κB ligand, inhibits the activation of osteoclasts. Some clinical trials have shown that denosumab suppresses bone resorption in patients with advanced cancer, but hypocalcemia has been reported as a serious adverse effect after the administration of denosumab. It is difficult to predict hypocalcemia in such cases because the risk factors for denosumab-induced hypocalcemia have not been reported. Accordingly, the aim of the present study was to identify the risk factors for hypocalcemia induced by denosumab. We retrospectively reviewed the records of patients who had received denosumab at Tokushima University Hospital between April 2012 and May 2013. Fifty-three patients were analyzed and eleven patients had hypocalcemia after administration of denosumab. Univariate logistic regression analysis revealed that the patients who had not been administered zoledronic acid before receiving denosumab or had lower creatinine clearance (CCr) appeared to have a higher risk of hypocalcemia (p<0.05). The cut off value of CCr was 50.4 ml/min calculated by receiver-operator characteristics curves. Moreover, multivariate logistic regression analysis revealed that non-administration of zoledronic acid (odds ratio 10.43, p<0.05) and CCr less than 50.0 ml/min (odds ratio 5.90, p<0.05) were independent risk factors for denosumab-induced hypocalcemia. These findings provide useful information regarding the monitoring of hypocalcemia in patients receiving denosumab.
[Show abstract][Hide abstract] ABSTRACT: Podoplanin (Aggrus), which is a type I transmembrane sialomucin-like glycoprotein, is highly expressed in malignant pleural mesothelioma (MPM). We previously reported the generation of a rat anti-human podoplanin Ab, NZ-1, which inhibited podoplanin-induced platelet aggregation and hematogenous metastasis. In this study, we examined the antitumor effector functions of NZ-1 and NZ-8, a novel rat-human chimeric Ab generated from NZ-1 including Ab-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity against MPM in vitro and in vivo. Immunostaining with NZ-1 showed the expression of podoplanin in 73% (11 out of 15) of MPM cell lines and 92% (33 out of 36) of malignant mesothelioma tissues. NZ-1 could induce potent ADCC against podoplanin-positive MPM cells mediated by rat NK (CD161a(+)) cells, but not murine splenocytes or human mononuclear cells. Treatment with NZ-1 significantly reduced the growth of s.c. established tumors of MPM cells (ACC-MESO-4 or podoplanin-transfected MSTO-211H) in SCID mice, only when NZ-1 was administered with rat NK cells. In in vivo imaging, NZ-1 efficiently accumulated to xenograft of MPM, and its accumulation continued for 3 wk after systemic administration. Furthermore, NZ-8 preferentially recognized podoplanin expressing in MPM, but not in normal tissues. NZ-8 could induce higher ADCC mediated by human NK cells and complement-dependent cytotoxicity as compared with NZ-1. Treatment with NZ-8 and human NK cells significantly inhibited the growth of MPM cells in vivo. These results strongly suggest that targeting therapy to podoplanin with therapeutic Abs (i.e., NZ-8) derived from NZ-1 might be useful as a novel immunotherapy against MPM.
The Journal of Immunology 05/2013; 190(12). DOI:10.4049/jimmunol.1300448 · 4.92 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Nifedipine is unstable under light and decomposes to a stable nitroso analog, nitrosonifedipine (NO-NIF). The ability of NO-NIF to block calcium channels is quite weak compared with that of nifedipine. Recently, we have demonstrated that NO-NIF reacts with unsaturated fatty acid leading to generate NO-NIF radical, which acquires radical scavenging activity. However, the effects of NO-NIF on the pathogenesis related with oxidative stress, such as atherosclerosis and hypertension, are unclear. In this study, we investigated the effects of NO-NIF on angiotensin II (Ang II)-induced vascular remodeling. Ang II-induced thickening and fibrosis of aorta were inhibited by NO-NIF in mice. NO-NIF decreased reactive oxygen species (ROS) in the aorta and urinary 8-hydroxy-20-deoxyguanosine. Ang II-stimulated mRNA expressions of p22(phox), CD68, F4/80, monocyte chemoattractant protein-1, and collagen I in the aorta were inhibited by NO-NIF. Moreover, NO-NIF inhibited Ang II-induced cell migration and proliferation of vascular smooth muscle cells (VSMCs). NO-NIF reduced Ang II-induced ROS to the control level detected by dihydroethidium staining and lucigenin chemiluminescence assay in VSMCs. NO-NIF suppressed phosphorylations of Akt and epidermal growth factor receptor induced by Ang II. However, NO-NIF had no effects on intracellular Ca(2+) increase and protein kinase C-δ phosphorylation induced by Ang II in VSMCs. The electron paramagnetic resonance spectra indicated the continuous generation of NO-NIF radical of reaction with cultured VSMCs. These findings suggest that NO-NIF improves Ang II-induced vascular remodeling via the attenuation of oxidative stress.
Archiv für Experimentelle Pathologie und Pharmakologie 11/2012; 386(1). DOI:10.1007/s00210-012-0810-7 · 2.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We previously found that plasma dipeptidyl peptidase 4 (DPP4) activity was associated with the development of obesity, type 2 diabetes, and type 1 diabetes using animal models. In this study, we investigated whether DPP4 activity is correlated with the clinical parameters of obesity and/or diabetes in healthy young subjects. Body mass index (BMI), plasma DPP4 activity, total cholesterol, high density lipoprotein (HDL) cholesterol, triglycerides, fasting blood glucose, adiponectin concentration, and body fat were measured in 165 subjects (110 males and 55 females, age 23.2 ± 2.4 years). In correlation analyses, DPP4 activity displayed strong positive correlations with BMI (p = 5.5 × 10(-5)) and total cholesterol (p = 0.0014), and a negative correlation with the plasma adiponectin concentration (p = 0.013), but not fasting blood glucose. Our findings suggest that plasma DPP4 activity is correlated with the clinical parameters of obesity rather than diabetes in young people.
[Show abstract][Hide abstract] ABSTRACT: Pseudomonas aeruginosa causes both invasive (bacteremic) and chronic noninvasive infections. An increase in intestinal epithelial permeability is a characteristic of severe sepsis. Alterations in the normal barrier function of the gut mucosa may result in the translocation of microbial cells and products. On the otherhand, it has been demonstrated that statin use is associated with a lower risk of mortality from bloodstream infections. Therefore, we investigated the ability of P. aeruginosa PAO1 to translocate across the Madin-Darby canine kidney (MDCK) cell monolayers in the presence and absence of simvastatin. The bacteria readily translocated across MDCK cell monolayers after 3 h of infection irrespective of the presence or absence of the drug in the medium. However, the bacteria were less able to penetrate the MDCK monolayers in the presence of simvastatin than in its absence. A gentamicin survival assay demonstrated that simvastatin did not affect the bacteria's invasive behavior in the MDCK cells.
The Journal of Medical Investigation 02/2012; 59(1-2):186-91. DOI:10.2152/jmi.59.186
[Show abstract][Hide abstract] ABSTRACT: Iron is an essential trace metal for most organisms. However, excess iron causes oxidative stress through production of highly toxic hydroxyl radicals via the Fenton/Haber-Weiss reaction. Iron storage in the body is reported to be associated with fat accumulation and type 2 diabetes mellitus. We investigated the role of iron in adiposity by using KKAy mice and obese and diabetic model mice. Eight-week-old KKAy mice were divided into two groups and treated with deferoxamine (DFO), an iron chelator agent, or a vehicle for 2 wk. DFO treatment diminished fat iron concentration and serum ferritin levels in KKAy mice. Fat weight and adipocyte size were reduced significantly in DFO-treated mice compared with vehicle-treated mice. Macrophage infiltration into fat was also decreased in DFO-treated mice compared with vehicle-treated mice. Superoxide production and NADPH oxidase activity in fat, as well as urinary 8-hydroxy-2'-deoxyguanosine excretion, were decreased in KKAy mice after DFO treatment while p22(phox) expression in adipose tissue was diminished in such mice. Ferritin expression in the fat of DFO-treated KKAy mice was decreased. In addition, F4/80-positive cells also presented through both p22(phox) and ferritin expression. The mRNA expression levels of inflammatory cytokines were also reduced in fat tissue of DFO-treated mice. These findings suggest that reduction of iron levels ameliorates adipocyte hypertrophy via suppression of oxidative stress, inflammatory cytokines, and macrophage infiltration, thereby breaking a vicious cycle in obesity.
[Show abstract][Hide abstract] ABSTRACT: SDS-PAGE is one of the most powerful experimental techniques used for the separation of proteins, and most proteins are separated according to their molecular size by this technique. However, exceptional proteins showing abnormal behavior in SDS-PAGE gels are known to exist. Thermal aggregation, rarely observed with membrane proteins, is one of the exceptional behaviors of proteins during SDS-PAGE, but detailed characterization of this aggregation has not yet been achieved. In the present study, we found that a putative membrane protein, TMEM45B, very clearly showed properties of thermal aggregation when it was expressed in COS7 cells and subjected to SDS-PAGE. We dissected the region of TMEM45B responsible for this aggregation, and found that of the seven putative transmembrane domains, a region comprising the 4th to 7th ones was essential for the thermal aggregation properties. We also demonstrated that these transmembrane domains, 4th to 7th, of TMEM45B conferred thermal aggregation properties on other proteins, by fusing this amino acid sequence to target proteins. The molecular mechanism causing thermal aggregation by TMEM45B is still uncertain, but TMEM45B could be utilized as a nice model to show clear thermal aggregation in SDS-PAGE gels.
Protein Expression and Purification 05/2011; 77(1):118-23. DOI:10.1016/j.pep.2011.01.011 · 1.70 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Quercetin, a member of the bioflavonoids family, has been proposed to have anti-atherogenic, anti-inflammatory, and anti-hypertensive properties leading to the beneficial effects against cardiovascular diseases. It was recently demonstrated that quercetin 3-O-β-D-glucuronide (Q3GA) is one of the major quercetin conjugates in human plasma, in which the aglycone could not be detected. Although most of the in vitro pharmacological studies have been carried out using only the quercetin aglycone form, experiments using Q3GA would be important to discover the preventive mechanisms of cardiovascular diseases by quercetin in vivo. Therefore we examined the effects of the chemically synthesized Q3GA, as an in vivo form, on vascular smooth muscle cell (VSMC) disorders related to the progression of arteriosclerosis. Platelet-derived growth factor-induced cell migration and proliferation were inhibited by Q3GA in VSMCs. Q3GA attenuated angiotensin II-induced VSMC hypertrophy via its inhibitory effect on JNK and the AP-1 signaling pathway. Q3GA scavenged 1,1-diphenyl-2-picrylhydrazyl radical measured by the electron paramagnetic resonance method. In addition, immunohistochemical studies with monoclonal antibody 14A2 targeting the Q3GA demonstrated that the positive staining specifically accumulates in human atherosclerotic lesions, but not in the normal aorta. These findings suggest Q3GA would be an active metabolite of quercetin in plasma and may have preventative effects on arteriosclerosis relevant to VSMC disorders.
[Show abstract][Hide abstract] ABSTRACT: Effects of a time-varying magnetic field on cell volume regulation by hyposmotic stress in cultured bovine adrenal chromaffin cells were examined. Through regulatory volume decrease (RVD), cell volume of chromaffin cells that were incubated in a hypotonic medium initially increased, reached a peak and finally recovered to the initial value. Two hour exposure to a magnetic field and addition of cytochalasin D increased peak value and delayed return to initial value. Intracellular F-actin contents initially decreased but returned to normal levels after 10 sec. Two hour exposure to the magnetic field and addition of cytochalasin D continuously reduced the F-actin content. Results suggest that exposure to the magnetic field stimulated disruption of the actin cytoskeleton and that the disruption delayed the recovery to the volume prior to osmotic stress.
The Journal of Medical Investigation 02/2011; 58(1-2):95-105. DOI:10.2152/jmi.58.95
[Show abstract][Hide abstract] ABSTRACT: Altered dipeptidyl peptidase-4 (DPP4) activity during the progression of late-stage type 2 diabetes was measured in Otsuka Long-Evans Tokushima fatty (OLETF) rats. Compared with OLETF rats subjected to 30% food restriction, food-satiated OLETF rats exhibited spontaneous hyperphagic obesity, insulin resistance, hyperglycemia, hyperinsulinemia, and increased plasma DPP4 activity during the early phase of the experiment (up to ∼30 wk). Subsequently, their plasma DPP4 activity as well as their body weight, body fat, and plasma insulin concentration declined to control levels during the late phase, resulting in excessive polyuria, proteinuria, dyslipidemia, pancreatic islet atrophy, hypoinsulinemia, and diabetes, which changed from insulin-resistant diabetes to hypoinsulinemic diabetes secondary to progressive islet insufficiency, and their fasting blood glucose level remained high. Since plasma DPP4 activity demonstrated significant positive correlations with body weight and the fasting plasma insulin level but not with the fasting blood glucose level during the late stage of diabetes, body fat and fasting plasma insulin levels may be useful factors for predicting the control of plasma DPP4 activity. In contrast, pancreatic DPP4 activity was significantly increased, and the expression of pancreatic insulin was significantly reduced in late-stage diabetic OLETF rats, suggesting that a relationship exists between the activation of pancreatic DPP4 and insulin depletion in pancreatic islet atrophy. In conclusion, it is suggested that plasma DPP4 activity changes in accordance with the progression of hyperinsulinemic obesity and pancreatic islet atrophy. DPP4 activity may play an important role in insulin homeostasis.