Safety and efficacy of nivolumab and standard chemotherapy drug combination in patients with advanced non-small-cell lung cancer: a four arms phase Ib study

In this phase Ib study, four combination therapies of nivolumab 10 mg/kg and standard chemotherapy (cisplatin/gemcitabine, cisplatin/pemetrexed, carboplatin/paclitaxel/bevacizumab, or docetaxel) showed acceptable toxicity profiles in patients with advanced non-small-cell lung cancer. Furthermore, these combination therapies presented encouraging antitumor activities.

Background

The human IgG4 monoclonal antibody nivolumab targets programmed cell death-1 (PD-1) and promotes antitumor response by blocking the interaction of PD-1 with its ligands. This single-center phase Ib study investigated the tolerability, safety, and pharmacokinetics of nivolumab combined with standard chemotherapy in patients with advanced non-small-cell lung cancer (NSCLC).

Patients and methods

Patients who had stage IIIB without indication for definitive radiotherapy, stage IV, or recurrent NSCLC were eligible. Regimens were nivolumab 10 mg/kg + gemcitabine/cisplatin (arm A), pemetrexed/cisplatin (arm B), paclitaxel/carboplatin/bevacizumab (arm C), or docetaxel (arm D). Regimens A, B, and D were repeated every 3 weeks for up to four cycles and regimen C was repeated for up to six cycles; nivolumab alone (arm A), with pemetrexed (arm B), bevacizumab (arm C), or docetaxel (arm D) was continued every 3 weeks as maintenance therapy until disease progression or unacceptable toxicity. Dose-limiting toxicity (DLT) was evaluated during the first treatment cycle.

Results

As of March 2014, six patients were enrolled in each arm. The combination of nivolumab 10 mg/kg and chemotherapy was well tolerated. DLT was observed in only one patient in arm A (alanine aminotransferase increased). Select adverse events (those with a potential immunologic cause) of any grade were observed in six, four, six, and five patients in arms A, B, C, and D, respectively. Three, three, six, and one patient achieved partial response while median progression-free survival was 6.28, 9.63 months, not reached, and 3.15 months in arms A, B, C, and D, respectively.

Conclusions

Combination of nivolumab 10 mg/kg and chemotherapy showed an acceptable toxicity profile and encouraging antitumor activity in patients with advanced NSCLC.

Clinical trials number

Japanese Pharmaceutical Information Center Clinical Trials Information (JapicCTI)-132071.

Galacto-N-biose is neuroprotective against glutamate-induced excitotoxicity in vitro

Galacto-N-biose (GNB: Galβ1-3GalNAc) is an O-glycan disaccharide core moiety that is a core component of mucin in the gastrointestinal tract; however, the physiological properties of GNB are not well understood. Glutamate excitotoxicity causes neuronal death in acute neurological disorders including stroke, trauma, and neurodegenerative disease. Therefore the discovery of drugs to treat glutamate excitotoxicity is an important goal. Here, we report that GNB is neuroprotective against glutamate-induced excitotoxicity. We treated 14-15 days in vitro cultured rat cortical neurons with 0.1-1000nM GNB together with 30µm glutamate for various durations. Short-term (3h) GNB treatments showed a modest neuroprotective effect against glutamate neurotoxicity, however, long-term (24h) GNB treatment conferred significant neuroprotective effects, as shown by both MTT and immunocytochemical assays. Prolonged GNB treatment did not alter glutamate-induced calcium influx, but did induce antioxidant-related gene expression. Furthermore, GNB treatment did not induce cell death or alter synaptic connections. These data suggest that GNB is a potential candidate drug that protects against glutamate excitotoxicity without affecting cell viability and synaptic connections.

Application of Expandable Metallic Stents to the Venous System

Expandable metallic stents were successfully introduced in 12 patients; 6 with superior vena cava (SVC) obstruction due to tumor invasion or lymph node metastases, 3 with inferior vena cava (IVC) obstruction or stenosis due to lymph node metastases or hepatic tumor, one with common iliac vein (CIV) obstruction due to lymph node metastases, one with idiopathic obstruction of the hepatic IVC and Budd-Chiari syndrome, and one with CIV obstruction following a dialysis shunt. The length of the lesions was between 2 and 15 cm. Multiple (2–7) stents in tandem were inserted percutaneously from a femoral venous approach through a 12 to 16 F (4.0–5.3 mm) Teflon sheath. Postoperatively, all 12 patients became free from symptoms such as SVC syndrome or IVC syndrome. In 11 patients, the symptoms did not recur during the follow-up periods of 1 to 21 months.

Endotracheal Expandable Metallic Stent Placement in Dogs

Various types of Gianturco zig-zag wire stent were implanted into the tracheas of 4 dogs to define the suitable characteristics of the endotracheal wire stent in these animals. The stents were constructed of 0.45, 0.40, and 0.33 mm stainless steel wire. The diameter of the fully expanded stents was 3 cm and their lengths were 2, 3, and 4 cm. The 2 cm stent constructed of 0.33 mm wire showed minimum pathologic changes of the trachea of the dog compared to the other stents, and at the same time had a complete covering of ciliated columnar epithelium over the stent surface.

Mr Imaging of Chronic Alcoholism

We evaluated the brain lesions of patients with chronic alcoholism (n = 34) in comparison with age- and sex-matched controls (n = 40) by MR imaging. T1-weighted sagittal and axial images and T2-weighted axial images were obtained with a 0.5 T superconducting MR unit. Various brain measurements were then performed, and the presence of regions of abnormal signal intensity was also compared between the two groups. The brain measurements revealed significant cerebral atrophy (characterized by lateral and 3rd ventricular dilatation, and widening of the interhemispheric fissure) as well as significant cerebellar atrophy (represented by 4th ventricular dilatation) in the alcoholic group. These changes were more prominent in patients in their fifties and sixties than in those aged in the thirties and forties. Focal hypointense lesions were observed in 20.6% of the alcoholics and in 5% of the controls (p < 0.01), while focal hyperintense lesions were observed in 61.8% of the alcoholics and in 20% of the controls (p < 0.001). The severity of these MR findings correlated well with the age of the patients. These observations suggest that alcohol is an important promotor of brain aging.

Treatment of Tuberculous Bronchial Stenosis with Expandable Metallic Stents

Gianturco expandable metallic stents were placed in 5 patients with dyspnea on exercise due to tuberculous bronchial stenosis. The stents were placed after dilatation with a 10-mm diameter high pressure balloon catheter. In all 5 patients, obstructive changes disappeared following the procedure, and dyspnea on exercise improved markedly. No complications related to the procedure were encountered. At follow-up during a period of up to 38 months, 2 patients showed bronchial restenosis at 11 and 17 months, respectively, after stent placement. Restenosis by granulomatous tissue was successfully treated by laser ablation. One patient showed slight one-day hemoptysis 26 months after stent placement.

Transcriptional Induction of Metallothionein by Tris(pentafluorophenyl)stibane in Cultured Bovine Aortic Endothelial Cells

Vascular endothelial cells cover the luminal surface of blood vessels and contribute to the prevention of vascular disorders such as atherosclerosis. Metallothionein (MT) is a low molecular weight, cysteine-rich, metal-binding, inducible protein, which protects cells from the toxicity of heavy metals and active oxygen species. Endothelial MT is not induced by inorganic zinc. Adequate tools are required to investigate the mechanisms underlying endothelial MT induction. In the present study, we found that an organoantimony compound, tris(pentafluorophenyl)stibane, induces gene expression of MT-1A and MT-2A, which are subisoforms of MT in bovine aortic endothelial cells. The data reveal that MT-1A is induced by activation of both the MTF-1-MRE and Nrf2-ARE pathways, whereas MT-2A expression requires only activation of the MTF-1-MRE pathway. The present data suggest that the original role of MT-1 is to protect cells from heavy metal toxicity and oxidative stress in the biological defense system, while that of MT-2 is to regulate intracellular zinc metabolism.

AU-1 from Agavaceae plants causes transient increase in p21/Cip1 expression in renal adenocarcinoma ACHN cells in an miR-34-dependent manner

Here, we show that AU-1, spirostanol saponin isolated from Agavaceae plants, causes a transient increase in cyclin-dependent kinase inhibitor (CDKI) p21/Cip1 through the upregulation of miRNAs, miR-34 and miR-21. AU-1 stimulated p21/Cip1 expression without exerting cytotoxicity against different types of carcinoma cell lines. In renal adenocarcinoma ACHN cells, AU-1 transiently elevated the expression level of p21/Cip1 protein without marked increases in p21/Cip1 mRNA levels. Rapid and transient increases in miR-34 and miR-21, both of which are known to upregulate p21/Cip1, were observed in AU-1-treated cells. Inhibitor for miR-34 and for miR-21 significantly blocked the AU-1-caused increase in p21/Cip1, indicating that elevation of p21/Cip1 protein by AU-1 is dependent on these microRNAs. We further clarified that NAD-dependent deacetylase SIRT1, a direct target of miR-34, is decreased by the treatment with AU-1. Furthermore, we found that SIRT1-knockdown increases p21/Cip1 protein levels in an miR-21-dependent manner. On the other hand, ectopic expression of p21/Cip1 resulted in the lowered expression of miR-34 and miR-21, suggesting that reciprocal regulation exists between p21/Cip1 and these miRNAs. We propose that the following feedback network composed of miR-34/SIRT1/miR-21/p21 is triggered by the treatment with AU-1: in cells treated with AU-1, transient elevation of miR-34 leads to the downregulation of SIRT1, thereby miR-21 is freed from SIRT1-dependent suppression. Then, elevated miR-21 upregulates p21/Cip1 protein, followed by the suppression of miR-34 expression.

Plasma concentrations of coffee polyphenols and plasma biomarkers of diabetes risk in healthy Japanese women

Coffee consumption has been reported to reduce the risk of type 2 diabetes in experimental and epidemiological studies. This anti-diabetic effect of coffee may be attributed to its high content in polyphenols especially caffeic acid and chlorogenic acid. However, the association between plasma coffee polyphenols and diabetic risks has never been investigated in the literature. In this study, fasting plasma samples were collected from 57 generally healthy females aged 38-73 (mean 52, s.d. 8) years recruited in Himeji, Japan. The concentrations of plasma coffee polyphenols were determined by liquid chromatography coupled with mass tandem spectrometer. Diabetes biomarkers in the plasma/serum samples were analysed by a commercial diagnostic laboratory. Statistical associations were assessed using Spearman's correlation coefficients. The results showed that plasma chlorogenic acid exhibited negative associations with fasting blood glucose, glycated hemoglobin and C-reactive protein, whereas plasma total coffee polyphenol and plasma caffeic acid were weakly associated with these biomarkers. Our preliminary data support previous findings that coffee polyphenols have anti-diabetic effects but further replications with large samples of both genders are recommended.

Novel prognostic prediction models for patients with stage IV colorectal cancer after concurrent curative resection

BACKGROUND

We developed a prediction tool for recurrence and survival in patients with stage IV colorectal cancer (CRC) following surgically curative resection.

PATIENTS AND METHODS

From January 1983 to December 2012, 113 patients with CRC and synchronous liver and/or lung metastatic CRC were investigated at the Osaka Medical Center for Cancer and Cardiovascular Diseases. All patients underwent curative resection of primary and metastatic lesions. In the group of patients who underwent surgery from 1983 to 2008, a Cox regression model was used to develop prediction models for 1-year, 3-year and 5-year cancer-specific survival (CSS) and relapse-free survival (RFS). In the other group of patients who underwent surgery from 2009 to 2012, the developed prediction model was validated.

RESULTS

Univariate analysis of clinicopathological factors showed that the following factors were significantly correlated with CSS and RFS: preoperative serum carcinoembryonic antigen level, tumour location, pathologically defined tumour invasion and lymph node metastasis, and synchronous metastatic lesions. Using these variables, novel prediction models predicting CSS and RFS were constructed using the Cox regression model with concordance indexes of 0.802 for CSS and 0.631 for RFS. The prediction models were validated by external data sets in an independent patient group.

CONCLUSIONS

We developed novel and reliable personalised prognostic models, integrating tumour, node, metastasis (TNM) factors as well as the preoperative serum carcinoembryonic antigen level, tumour location and metastatic lesions, to predict patients' prognosis following surgically curative resection. This individualised prediction model may help clinicians in the treatment of postoperative stage IV CRC following surgically curative resection.

Copper diethyldithiocarbamate as an activator of Nrf2 in cultured vascular endothelial cells

The interest in organic-inorganic hybrid molecules as molecular probes for biological systems has been growing rapidly. Such hybrid molecules exhibit unique biological activities. Herein, copper(II) bis(diethyldithiocarbamate) (Cu10) was found to activate the transcription factor NF-E2-related factor 2 (Nrf2), which is responsible for regulating antioxidant and phase II xenobiotic enzymes, in vascular endothelial cells. The copper complex rapidly accumulated within cells and induced nuclear translocation of Nrf2, leading to upregulation of the expression of downstream proteins without cytotoxic effects. However, while copper bis(2-hydroxyethyl)dithiocarbamate activated Nrf2, copper ion, diethyldithiocarbamate ligand with or without zinc or iron failed to exhibit this activity. Intracellular accumulation of Cu10 was higher than that of Cu(II) and Cu(I). While the accumulation of copper(II) bis(dimethyldithiocarbamate) was reduced by small interfering RNA (siRNA)-mediated knockdown of the copper transporter CTR1, the knockdown did not affect Cu10 accumulation, indicating that Cu10 rapidly enters vascular endothelial cells via CTR1-independent mechanisms. In addition, copper and iron complexes with other ligands tested could not activate Nrf2, suggesting that the intramolecular interaction between copper and dithiocarbamate ligand is important for the activation of the transcription factor. Cu10 induced the expression of heme oxygenase-1, NAD(P)H quinone oxidoreductase 1, and γ-glutamylcysteine synthetase, downstream proteins of Nrf2. It was suggested that Cu10-induced activation of Nrf2 was due to proteasome inhibition as well as binding to Kelch-like ECH-associated protein 1. Since the effects of Cu10 on vascular endothelial cells are unique and diverse, the copper complex may be a good molecular probe to analyze the functions of the cells.

Characteristics of nighttime reflux assessed using multichannel intraluminal impedance pH monitoring and a portable electroencephalograph

Gastroesophageal reflux disease (GERD) is strongly associated with sleep disturbances. Although the mechanisms of this association have not been fully elucidated, nighttime reflux plays a central role. However, the detailed characteristics of nighttime reflux occurring during sleep are unknown. The aim of the present study was to examine the characteristics and prevalence of nighttime reflux in the natural sleep environment of GERD patients. Seventeen patients experiencing daily moderate-to-severe heartburn and/or regurgitation were studied using multichannel intraluminal impedance pH monitoring and electroencephalography off-proton pump inhibitor treatment. Nighttime reflux was divided based on reflux type (liquid or gas), acidity (acidic, weakly acidic, or alkaline) and extent (distal only or proximal migration) according to the standard criteria. Nighttime phases were divided as follows: recumbent-awake before falling asleep, nonrapid eye movement, rapid eye movement, awakening from sleep, and post-awakening in the morning. Among 184 nighttime refluxes, 43 (23%) occurred during recumbent-awake before falling asleep, 28 (15%) during nonrapid eye movement, 14 (8%) during rapid eye movement, 86 (46%) during awakening from sleep, and 13 (7%) during post-awakening in the morning. Liquid reflux was more common in awakening during sleep (92%), nonrapid eye movement (100%), and rapid eye movement (100%) compared with awakening before falling asleep (68%). The prevalence of proximal migration was significantly lower in nonrapid eye movement and rapid eye movement than in the other phases. There were no differences in acidity and bolus clearance time among the phases. Thirteen (65%) of 20 events with GERD symptoms had nighttime reflux, suggesting that only 7.1% (13 of 184) of nighttime refluxes were symptomatic. Nighttime reflux was observed in 48 (11%) of 425 awakening episodes during sleep. Different reflux patterns at each phase during nighttime might explain the pathogenesis of GERD and its related sleep disturbances.

Induction of metallothionein isoforms by copper diethyldithiocarbamate in cultured vascular endothelial cells

Metallothionein (MT) plays a central role in cellular defense against heavy metals and oxidative stress. Since the induction of MT requires the activation of metal response element (MRE)-binding transcription factor-1 (MTF-1) by binding of zinc ions, inorganic zinc is regarded as a typical MT inducer. However, in a previous report, we showed that inorganic zinc could not induce MT in vascular endothelial cells. While it is suggested that endothelial MT presents mechanisms different from those of other cell types, these remain unclear. In this study, we investigated whether the induction of endothelial MT expression involves the Nrf2-ARE pathway using copper(II) bis(diethyldithiocarbamate), termed Cu10, using a culture system of bovine aortic endothelial cells. Cu10 induced MT-1/2 protein expression and increased the expression of mRNAs for MT-1A, MT-1E, and MT-2, MT isoforms expressed in the cells. Cu10 activated not only the MTF-1-MRE, but also the Nrf2-ARE pathway. MTF-1 knockdown resulted in the repression of Cu10-induced MT-1 and -2 expression. Cu10-induced MT-1 expression was down-regulated by Nrf2 knockdown. However, MT-2 expression was not affected by Nrf2 knockdown. These results suggest that the expression of endothelial MT is up-regulated by the Nrf2-ARE pathway as well as by the MTF-1-MRE pathway. Moreover, MT-1 regulation mechanisms differ from that of MT-2. Specifically, the present data support the hypothesis that MT-1 participates in the biological defense system, while MT-2 mainly regulates intracellular zinc metabolism.

Measurement and comparison of individual external doses of high-school students living in Japan, France, Poland and Belarus-the 'D-shuttle' project

Twelve high schools in Japan (of which six are in Fukushima Prefecture), four in France, eight in Poland and two in Belarus cooperated in the measurement and comparison of individual external doses in 2014. In total 216 high-school students and teachers participated in the study. Each participant wore an electronic personal dosimeter 'D-shuttle' for two weeks, and kept a journal of his/her whereabouts and activities. The distributions of annual external doses estimated for each region overlap with each other, demonstrating that the personal external individual doses in locations where residence is currently allowed in Fukushima Prefecture and in Belarus are well within the range of estimated annual doses due to the terrestrial background radiation level of other regions/countries.

Accumulation of p53 via down-regulation of UBE2D family genes is a critical pathway for cadmium-induced renal toxicity

Chronic cadmium (Cd) exposure can induce renal toxicity. In Cd renal toxicity, p53 is thought to be involved. Our previous studies showed that Cd down-regulated gene expression of the UBE2D (ubiquitin-conjugating enzyme E2D) family members. Here, we aimed to define the association between UBE2D family members and p53-dependent apoptosis in human proximal tubular cells (HK-2 cells) treated with Cd. Cd increased intracellular p53 protein levels and decreased UBE2D2 and UBE2D4 gene expression via inhibition of YY1 and FOXF1 transcription factor activities. Double knockdown of UBE2D2 and UBE2D4 caused an increase in p53 protein levels, and knockdown of p53 attenuated not only Cd-induced apoptosis, but also Cd-induced apoptosis-related gene expression (BAX and PUMA). Additionally, the mice exposed to Cd for 6 months resulted in increased levels of p53 and induction of apoptosis in proximal tubular cells. These findings suggest that down-regulation of UBE2D family genes followed by accumulation of p53 in proximal tubular cells is an important mechanism for Cd-induced renal toxicity.

Abstract P3-07-45: Bone turnover marker levels and clinical outcomes in patients with breast cancer and bone metastases treated with bone antiresorptive therapies

INTRODUCTION AND OBJECTIVES: Patients with advanced breast cancer (BC) and metastatic bone disease typically have elevated serum levels of bone turnover markers (BTMs). Potent antiresorptive agents, such as denosumab and zoledronic acid, can significantly reduce BTM levels (Stopeck et al. J Clin Oncol 2010). Prior studies have provided evidence that higher BTM baseline levels may be associated with worse clinical outcomes (Ali et al. Ann Oncol 2004). In this analysis, we assessed the association between BTM levels after treatment with antiresorptive agents and overall survival (OS), disease progression (DP) and disease progression in the bone (DPB) in patients with advanced BC and bone metastases.

METHODS: This post-hoc analysis included data from patients with BC and bone metastases enrolled in an international, blinded phase 3 trial who were randomized to receive either denosumab (120 mg SC) or zoledronic acid (4 mg IV, adjusted for creatinine clearance). The BTMs urinary N-telopeptide (uNTx) and bone-specific alkaline phosphatase (BSAP) were measured at study entry and at study month 3. The clinical outcomes of OS, DP, and DPB were compared in patients with BTMs above or below median levels at month 3 of antiresorptive therapy. These covariate analyses were based on Cox models stratified by treatment, prior SRE before month 3, prior bisphosphonate use, chemotherapy at randomization, and region (Japan or other countries).

RESULTS: A total of 1705 patients were measured for uNTx serum levels, with 895 patients ≥ and 810 &lt; the median of 10.40 nmol/mmol at month 3. Similarly, BSAP levels were measured in a total of 1708 patients, with 855 patients ≥ and 853 &lt; the median BSAP level of 10.89 ng/mL at month 3. Patients with uNTx levels ≥ the median at month 3 had a significantly reduced OS (by 54%) and a greater risk of both DP (by 21%) and DPB (by 23%) than patients with uNTx levels &lt; median (see Table). Similarly, patients with BSAP levels ≥ the median level at month 3 had an increased risk for reduced OS (by 197%), DP (by 67%) and DPB (by 56%) compared with patients whose BSAP levels &lt; median. After adjusting for risk factors suggestive of more advanced disease such as visceral metastases or &gt; 2 bone metastases, the correlation between elevated BTMs and reduced OS and greater risk of DP and DPB was maintained.

CONCLUSIONS: Patients with BTM levels ≥ median at month 3 of antiresorptive therapy had generally worse clinical outcomes than patients whose BTM levels were &lt; median. Assessment of uNTx and BSAP serum levels after treatment with antiresorptive therapy can add to our understanding of which patients with breast cancer and bone metastases are most at risk for decreased OS, or increased DP or DPB.

Month 3*Covariate Analysis Results: Risk of Decreased OS or Increased DP or DPBClinical OutcomeHazard Ratio (95% Confidence Interval)P-valueDecrease in OSuNTXa1.539 (1.270, 1.866)&lt;0.0001BSAPb2.966 (2.422, 3.633)&lt;0.0001Increase in DPuNTXa1.214 (1.071, 1.377)=0.0024BSAPb1.666 (1.470, 1.888)&lt;0.0001Increase of DPBuNTXa1.231 (1.054, 1.437)=0.0087BSAPb1.563 (1.342, 1.821)&lt;0.0001*Comparing ≥ median to &lt; median. aMedian uNTx levels=10.40 nmol/mmol. bMedian BSAP level=10.89 ng/mL.

Citation Format: Lipton A, Stopeck A, Body J-J, Von Moos R, De Boer R, Paiva Gadelha Guimaraes A, Tonkin K, Fujiwara Y, Zhu L, Warner D. Bone turnover marker levels and clinical outcomes in patients with breast cancer and bone metastases treated with bone antiresorptive therapies. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-45.

Effects of a dielectric material in an ion source on the ion beam current density and ion beam energy

To understand a strong focusing phenomenon that occurs in a low-energy hydrogen ion beam, the electron temperature, the electron density, and the space potential in an ion source with cusped magnetic fields are measured before and after the transition to the focusing state using an electrostatic probe. The experimental results show that no significant changes are observed before or after the transition. However, we found unique phenomena that are characterized by the position of the electrostatic probe in the ion source chamber. Specifically, the extracted ion beam current density and energy are obviously enhanced in the case where the electrostatic probe, which is covered by a dielectric material, is placed close to an acceleration electrode.

Different Regulation of p53 Expression by Cadmium Exposure in Kidney, Liver, Intestine, Vasculature, and Brain Astrocytes

Chronic exposure to cadmium (Cd) is known to adversely affect renal function. Our previous studies indicated that Cd induces p53-dependent apoptosis by inhibiting gene expression of the ubiquitin-conjugating enzyme (Ube) 2d family in both human and rat proximal tubular cells. In this study, the effects of Cd on protein expression of p53 and apoptotic signals in the kidney and liver of mice exposed to Cd for 12 months were examined, as well as the effects of Cd on p53 protein levels and gene expression of the Ube2d family in various cell lines. Results showed that in the kidney of mice exposed to 300 ppm Cd for 12 months, there was overaccumulation of p53 proteins in addition to the induction of apoptosis, which was triggered specifically in the proximal tubules. Interestingly, the site of apoptosis was the same as that of p53 accumulation in the proximal tubules. In the liver of mice chronically exposed to Cd, gene expression of the Ube2d family tended to be slightly decreased, together with slight apoptosis without the accumulation of p53 protein. In rat small intestine epithelial (IEC-6) cells, Cd decreased not only the p53 protein level but also gene expression of Ube2d1, Ube2d2 and Ube2d4. In human brain microvascular endothelial cells (HBMECs), Cd did not suppress gene expression of the Ube2d family, but increased the p53 protein level. In human brain astrocytes (HBASTs), Cd only increased gene expression of UBE2D3. These results suggest that Cd-induced apoptosis through p53 protein is associated with renal toxicity but not hepatic toxicity, and the modification of p53 protein by Cd may vary depending on cell type.

Utilization of native oxygen in Eu(RE)-doped GaN for enabling device compatibility in optoelectronic applications

The detrimental influence of oxygen on the performance and reliability of V/III nitride based devices is well known. However, the influence of oxygen on the nature of the incorporation of other co-dopants, such as rare earth ions, has been largely overlooked in GaN. Here, we report the first comprehensive study of the critical role that oxygen has on Eu in GaN, as well as atomic scale observation of diffusion and local concentration of both atoms in the crystal lattice. We find that oxygen plays an integral role in the location, stability, and local defect structure around the Eu ions that were doped into the GaN host. Although the availability of oxygen is essential for these properties, it renders the material incompatible with GaN-based devices. However, the utilization of the normally occurring oxygen in GaN is promoted through structural manipulation, reducing its concentration by 2 orders of magnitude, while maintaining both the material quality and the favorable optical properties of the Eu ions. These findings open the way for full integration of RE dopants for optoelectronic functionalities in the existing GaN platform.

High current density ion beam obtained by a transition to a highly focused state in extremely low-energy region

A high current density (≈3 mA/cm(2)) hydrogen ion beam source operating in an extremely low-energy region (E(ib) ≈ 150-200 eV) has been realized by using a transition to a highly focused state, where the beam is extracted from the ion source chamber through three concave electrodes with nominal focal lengths of ≈350 mm. The transition occurs when the beam energy exceeds a threshold value between 145 and 170 eV. Low-level hysteresis is observed in the transition when E(ib) is being reduced. The radial profiles of the ion beam current density and the low temperature ion current density can be obtained separately using a Faraday cup with a grid in front. The measured profiles confirm that more than a half of the extracted beam ions reaches the target plate with a good focusing profile with a full width at half maximum of ≈3 cm. Estimation of the particle balances in beam ions, the slow ions, and the electrons indicates the possibility that the secondary electron emission from the target plate and electron impact ionization of hydrogen may play roles as particle sources in this extremely low-energy beam after the compensation of beam ion space charge.

Enteric glial cells are associated with stress-induced colonic hyper-contraction in maternally separated rats

BACKGROUND

Enteric glial cells (EGCs) play important roles in enteric integrity and regulation of gastrointestinal function. However, whether EGCs undergo pathophysiological changes in stress-associated gastrointestinal disorders is unknown. We investigated structural and functional alterations in colonic EGCs and their roles in colonic contraction in an irritable bowel syndrome (IBS) model.

METHODS

As a chronic stress, male Wistar rats underwent 3-h maternal separation during postnatal days 2-14. As an acute stress, we used water-immersion stress (4 h) in adulthood (at 8 weeks). We quantitatively and morphologically evaluated enteric neurons and EGCs using whole-mount longitudinal muscle-myenteric plexus preparations. Colonic contraction was analyzed with electrical field stimulation (EFS).

KEY RESULTS

Glial fibrillary acidic protein (GFAP) expression and the number of total, cholinergic, and nitrergic neurons were unchanged in maternally separated rats with acute stress (combined stress: an IBS model) compared with controls. However, the density of GFAP-positive EGC processes that apparently overlapped with the neurons and the extent of bulbous swelling of terminals increased according to the stress intensity: control, acute stress, maternal separation, and combined stress. EFS-induced colonic contractions were significantly greater in the combined stress rats than in controls. Higher dose of fluorocitrate, a selective inhibitor of EGC metabolism, was required to inhibit both EFS-induced contraction and EGCs activation in the combined stress rats than in controls.

CONCLUSIONS & INFERENCES

Colonic EGCs exhibited structural alterations according to the stress intensity. EGCs were associated with stress-induced colonic hyper-contraction in the combined stress rats, which may underlie the pathogenesis of IBS.