Single-hole tunneling through a two-dimensional hole gas in intrinsic silicon

In this letter we report single-hole tunneling through a quantum dot in a two-dimensional hole gas, situated in a narrow-channel field-effect transistor in intrinsic silicon. Two layers of aluminum gate electrodes are defined on Si/SiO$_2$ using electron-beam lithography. Fabrication and subsequent electrical characterization of different devices yield reproducible results, such as typical MOSFET turn-on and pinch-off characteristics. Additionally, linear transport measurements at 4 K result in regularly spaced Coulomb oscillations, corresponding to single-hole tunneling through individual Coulomb islands. These Coulomb peaks are visible over a broad range in gate voltage, indicating very stable device operation. Energy spectroscopy measurements show closed Coulomb diamonds with single-hole charging energies of 5--10 meV, and lines of increased conductance as a result of resonant tunneling through additional available hole states.Comment: 4 pages, 4 figures. This article has been submitted to Applied Physics Letter

The Sequence of Delta24-RGD and TMZ Administration in Malignant Glioma Affects the Role of CD8+T Cell Anti-tumor Activity

The conditionally replicating oncolytic adenovirus Delta24-RGD (Ad) is currently under investigation in clinical trials for glioblastoma, including in combination with temozolomide (TMZ), the standard chemotherapy for this tumor. Previously, we showed that the efficacy of Delta24-RGD in a murine model is primarily dependent on the virus-induced anti-tumor immune response. As observed with most chemotherapies, TMZ has pronounced immune-modulating effects. Here, we studied the combined effects of these treatments in a murine glioma model. In vitro, we observed a synergistic activity between Delta24-RGD and TMZ. In vivo, C57BL/6 mice bearing intracranial GL261 tumors were treated with TMZ for 5 days either prior to intratumoral Delta24-RGD injection (TMZ/Ad) or post virus injection (Ad/TMZ). Notably, the Ad/TMZ regimen led to similar tumoral CD8+ T cell influx as the virus-only treatment, but increased the ability of CD8+ T cells to specifically recognize the tumor cells. This was accompanied by improved survival. The TMZ/Ad regimen also improved survival significantly compared to controls, but not compared to virus alone. In this group, the influx of dendritic cells is impaired, followed by a significantly lower number of tumor-infiltrating CD8+ T cells and no recognition of tumor cells. Depletion of either CD4+ T cells or CD8+ T cells impaired the efficacy of Delta24-RGD, underscoring the role of these cells in therapeutic activity of the virus. Overall, we show that the addition of TMZ to Delta24-RGD treatment leads to a significant increase in survival and that the order of sequence of these treatments affects the CD8+T cell anti-tumor activity

National laboratory-based surveillance system for antimicrobial resistance: a successful tool to support the control of antimicrobial resistance in the Netherlands

An important cornerstone in the control of antimicrobial resistance (AMR) is a well-designed quantitative system for the surveillance of spread and temporal trends in AMR. Since 2008, the Dutch national AMR surveillance system, based on routine data from medical microbiological laboratories (MMLs), has developed into a successful tool to support the control of AMR in the Netherlands. It provides background information for policy making in public health and healthcare services, supports development of empirical antibiotic therapy guidelines and facilitates in-depth research. In addition, participation of the MMLs in the national AMR surveillance network has contributed to sharing of knowledge and quality improvement. A future improvement will be the implementation of a new semantic standard together with standardised data transfer, which will reduce errors in data handling and enable a more real-time surveillance. Furthermore, the

The HDAC Inhibitors Scriptaid and LBH589 Combined with the Oncolytic Virus Delta24-RGD Exert Enhanced Anti-Tumor Efficacy in Patient-Derived Glioblastoma Cells

Background A phase I/II trial for glioblastoma with the oncolytic adenovirus Delta24-RGD was recently completed. Delta24-RGD conditionally replicates in cells with a disrupted retinoblastomapathway and enters cells via av beta 3/5 integrins. Glioblastomas are differentially sensitive to Delta24-RGD. HDAC inhibitors (HDACi) affect integrins and share common cell death pathways with Delta24-RGD. We studied the combination treatment effects of HDACi and Delta24-RGD in patient-derived glioblastoma stem-like cells (GSC), and we determined the most effective HDACi. Methods SAHA, Valproic Acid, Scriptaid, MS275 and LBH589 were combined with Delta24-RGD in fourteen distinct GSCs. Synergy was determined by Chou Talalay method. Viral infection and replication were assessed using luciferase and GFP encoding vectors and hexon-titration assays. Coxsackie adenovirus receptor and av beta 3 integrin levels were determined by flow cytometry. Oncolysis and mechanisms of cell death were studied by viability, caspase-3/7, LDH and LC3B/p62, phospho-p70S6K. Toxicity was studied on normal human astrocytes. MGMT promotor methylation status, TCGA classification, Rb-pathway and integrin gene expression levels were assessed as markers of responsiveness. Results Scriptaid and LBH589 acted synergistically with Delta24-RGD in approximately 50% of the GSCs. Both drugs moderately increased ava3 integrin levels and viral infection in responding but not in non-responding GSCs. LBH589 moderately increased late viral gene expression, however, virus titration revealed diminished viral progeny production by both HDACi, Scriptaid augmented caspase-3/7 activity, LC3B conversion, p62 and phosphop70S6K consumption, as well as LDH levels. LBH589 increased LDH and phosphop70S6K consumption. Responsiveness correlated with expression of various Rb-pathway genes and integrins. Combination treatments induced limited toxicity to human astrocytes. Conclusion LBH589 and Scriptaid combined with Delta24-RGD revealed synergistic anti-tumor activity in a subset of GSCs. Both HDACi moderately augmented viral infection and late gene expression, but slightly reduced progeny production. The drugs differentially activated multiple cell death pathways. The limited toxicity on astrocytes supports further evaluation of the proposed combination therapies

National laboratory-based surveillance system for antimicrobial resistance:a successful tool to support the control of antimicrobial resistance in the Netherlands

An important cornerstone in the control of antimicrobial resistance (AMR) is a well-designed quantitative system for the surveillance of spread and temporal trends in AMR. Since 2008, the Dutch national AMR surveillance system, based on routine data from medical microbiological laboratories (MMLs), has developed into a successful tool to support the control of AMR in the Netherlands. It provides background information for policy making in public health and healthcare services, supports development of empirical antibiotic therapy guidelines and facilitates in-depth research. In addition, participation of the MMLs in the national AMR surveillance network has contributed to sharing of knowledge and quality improvement. A future improvement will be the implementation of a new semantic standard together with standardised data transfer, which will reduce errors in data handling and enable a more real-time surveillance. Furthermore, the scientific impact and the possibility of detecting outbreaks may be amplified by merging the AMR surveillance database with databases from selected pathogen-based surveillance programmes containing patient data and genotypic typing data.</p

Grading of meningeal solitary fibrous tumors/hemangiopericytomas: analysis of the prognostic value of the Marseille Grading System in a cohort of 132 patients

The finding that meningeal solitary fibrous tumors (SFTs) and meningeal hemangiopericytomas (HPCs) are both characterized by NAB2‐STAT6 gene fusion has pushed their inclusion in the WHO 2016 Classification of tumors of the central nervous system (CNS) as different manifestations of the same entity. Given that the clinical behavior of the CNS SFT/HPC spectrum ranges from benign to malignant, it is presently unclear whether the grading criteria are still adequate. Here, we present the results of a study that analyzed the prognostic value of an updated version of the Marseille Grading System (MGS) in a retrospectively assembled cohort of 132 primary meningeal SFTs/HPCs with nuclear overexpression of STAT6. The median patient follow‐up was 64 months (range 4–274 months); 73 cases (55%) were MGS I, 50 cases (38%) MGS II and 9 cases (7%) were MGS III. Progression‐free survival (PFS) and disease‐specific survival (DSS) were investigated using univariate analysis: the prognostic factors for PFS included MGS, extent of surgery, radiotherapy, chemotherapy and mitotic activity ≥5/10 high‐power field (HPF). Moreover, MGS, radiotherapy, mitotic activity ≥5/10 HPF, and necrosis were the prognostic factors measured for DSS. In multivariate analysis, extent of surgery, mitotic activity ≥5/10 HPF, MGS I and MGS III were the independent prognostic factors measured for PFS while necrosis, MGS III and radiotherapy were the independent prognostic factors for DSS. In conclusion, our results show that assessing the malignancy risk of SFT/HPC should not rely on one single criterion like mitotic activity. Therefore, MGS is useful as it combines the value of different criteria. In particular, the combination of a high mitotic activity and necrosis (MGS III) indicates a particularly poor prognosis

EXPERIMENTAL THERAPEUTICS AND PHARMACOLOGY

The multifunctional protein - tissue inhibitor of metalloproteinases-1 (TIMP-1) - has been associated with poor prognosis in several types of cancers including glioblastomas. Glioblastomas are the most common and malignant primary brain tumor known for being highly invasive and resistant to therapy. New treatment strategies are continuously being explored and currently vascular endothelial growth factor (VEGF) inhibitors administered in combination with Irinotecan is the most promising second line treatment. TIMP-1 has been associated with decreased response to chemotherapy in breast and colorectal cancer and especially the family of topoisomerase (TOP) inhibitors, such as Irinotecan, has been suggested to be affected by TIMP-1. In the present study, we investigated whether a high TIMP-1 expression in glioblastoma cells played a role in TOP inhibitor resistance. We established two TIMP-1 over-expressing cell lines and evaluated the sensitivity towards the TOP1 inhibitor SN-38 and the TOP2 inhibitor Epirubicin using a viability and a cytotoxicity assay. In addition, we investigated the invasive features of the cells in a brain slice culture model as well as in an orthotopic xenograft model. The results showed that TIMP-1 over-expressing U87MG cell line sub-clones were significantly more resistant than the controls when exposed to SN-38 and Epirubicin. The same tendency was seen for the TIMP-1 over-expressing A172 sub-clones. No significant differences in invasion patterns were observed for TIMP-1 over-expressing sub-clones when compared to controls. In conclusion, the present study suggests that TIMP-1 over-expression reduces the effect of TOP inhibitors in the glioblastoma cell line U87MG. There was no significant effect of TIMP-1 over-expression on tumor cell invasion. The association found between TIMP-1 cellular levels and the effect of TOP inhibitors needs to be validated in clinical patient material. Pediatric supratentorial high-grade astrocytomas (pHGAs) and diffuse intrinsic pontine gliomas (DIPG) are devastating pediatric malignancies for which no effective therapies exist. Poly-(ADP-Ribose)-Polymerase (PARP) protein expression is found in ∼60% of DIPGs suggesting PARP may be a potential therapeutic target. PARP1/2 were characterized by Western-blotting in normal human astrocytes (NHA), pHGA cell lines (SJG2, SF-188), DIPG cell lines (DIPG-M, DIPG58), and one murine brainstem glioma cell line (mBSG). Cell viability in response to different dosages of Olaparib, Veliparib, or Niraparib was determined using the MTT Assay. PARP activity, apoptosis, and DNA damage was determined by Western blotting against PAR, cleaved PARP, and phosphorylated yH2AX, respectively. Cell cycle phases were analyzed using FACS and western blot for p21. Western blotting demonstrated that, compared with NHAs, PARP1 were highly expressed in SJG2, DIPG-M, and DIPG-58 cells. PARP2 expression was only detected in SJG2 cells. All PARP inhibitors reduced PARP activity as indicated by reduced PAR levels. Olaparib reduced SJG2, mBSG, DIPG58 and DIPGM cell viability at concentrations of 5 or 10uM uM (P &lt; 0.05), Whereas Niraparib induced cytotoxicity at concentrations of 2uM and above (P &lt; 0.05). Olaparib and Niraparib induced DNA damage and apoptosis in SJG2 at doses of 5, 10uM and 2, 5, 10uM, respectively. Niraparib induced G2 arrest in mBSG demonstrated by FACS and increased levels of p21 (P &lt; 0.05). Our data provides in vitro evidence that PARP inhibition may be an effective therapeutic avenue for treatment of pHGA and DIPG. Furthermore while all PARP inhibitors suppress PARP activity not all PARP inhibitors reduce cell viability. Thus not all PARP inhibitors can be expected to be equally efficacious in a clinical trial setting. Toca 511 (vocimagene amiretrorepvec), an amphotropic retroviral replicating vector (RRV), can successfully and safely deliver a functional, optimized yeast cytosine deaminase (CD) gene to tumors in orthotopic glioma models. Within infected cells, CD converts 5-fluorocytosine (5-FC) to the anti-cancer drug 5-FU. The combination of Toca 511 with oral extended release 5-FC (Toca FC), is currently in clinical trials for recurrent High Grade Glioma (HGG, NCT01156584 and NCT01470794). Temozolomide (TMZ), in combination with radiation therapy, is the most commonly used first-line chemotherapy treatment for patients with glioblastoma, the most common and aggressive form of primary brain cancer. A separate study (Takahashi et al., this meeting) addresses the potential radiation synergy with Toca 511/5-FC treatment. A subset of patients with certain genetic alterations does not respond well to TMZ treatment and the overall median survival for patients who respond remains poor, suggesting combinatorial approaches may be necessary to significantly improve patient outcomes. To determine whether Toca 511 and 5-FC therapy is compatible with TMZ, we examined the effect of TMZ in combination with Toca 511 and 5-FC in TMZ-sensitive and resistant glioma lines both in vitro and in vivo. We show that in vitro TMZ delays but does not prevent RRV spread, nor interfere with Toca 511 and 5-FC mediated cell killing in glioma tumor cells, and in vivo there is no significant hematologic effect from the combination of 5-FC and the clinically relevant dose of TMZ. A synergistic long-term survival advantage is observed in mice bearing an orthotopic TMZ-sensitive glioma tumor after Toca 511 administration followed by co-administration of TMZ in combination with 5-FC. These results provide support for the investigation of this novel combination treatment strategy for patients with newly diagnosed glioblastoma. BACKGROUND: LAZ is a 21-aminosteroid that has radioprotective effects against radiation-induced lipid peroxidation. Also antiproliferative effects have been reported against glioblastoma cell lines. DESIGN/METHODS: LAZ PEGylated liposomes (Lipo G) were developed at the University of Houston.. Glioblastoma cell line U87-expressing firefly luciferase reporter gene (100,000 cells in 2 µL) was injected intracranially in each SCID mouse. There were 4 treatment groups (n = 8-9, each): brain model (M) without treatment (control), radiation 2Gy weekly (M + R), Lipo G at 5 mg/kg dose intraperitoneally twice per week (M + L) and radiation with Lipo G (M + R + L). Treatment lasted three weeks. Tumor size was monitored using bioluminescence imaging (BLI), in each mouse. Mice were sacrificed after 3 weeks. Brain was harvested. Lipid peroxidation of brain tissues was quantified by measuring malondialdehyde (MDA) as a surrogate biomarker. Survival was evaluated using Kaplan Meier analysis at P= 0.05. RESULTS: BLI intensity was 4002.03 ± 1737.67, 2034 ± 737.72, 1387.36 ± 684.53 and 2498.89 ± 2521.32 % for M, M + R, M + L and M + R + L, respectively. Tumor size of the M + L group was reduced by 65% compared to control. There was no significant difference in tumor size of radiated groups compared to control group. MDA brain concentration in M + L and M + R + L groups was significantly less than in M + R group (8.27 ± 0.78 and 10.37 ± 3.30 µM/gm vs. 23.09± 3.79 µM/gm). The survival mean was 22.67, 25.33, 25.22 and 27.13 days for M, M + R, M + R + L and M + L groups, respectively. Mean survival of LAZ treated groups (M + L and M + R + L) was significantly longer than that of the control group. CONCLUSIONS: LAZ liposomal formulations reduced tumor growth by 65%. LAZ also protected brain tissue from radiation-induced lipid peroxidation by reducing MDA concentration by 50%. These provocative data warrant further investigation of LAZ as a radiation protectant and chemotherapeutic agent. Patients with malignant brain tumors have a median survival of approximately one year following diagnosis, regardless of currently available treatments which include surgery followed by radiation and chemotherapy. Improvement in the survival of brain cancer patients requires the design of new therapeutic modalities that take advantage of common phenotypes. One such phenotype is the metabolic dysregulation that is a hallmark of cancer cells. It has therefore been postulated that one approach to treating brain tumors may be by metabolic alteration such as that which occurs through the use of the ketogenic diet (KD). The KD is high-fat, low-carbohydrate diet that induces ketosis and has been utilized for the non-pharmacologic treatment of refractory epilepsy. We and others have shown that this diet enhances survival and potentiates standard therapy in mouse models of malignant gliomas, yet the anti-tumor mechanisms are not fully understood. It has been previously shown that caloric restriction, which induces ketosis, reduces microvessel density in mouse and human brain tumor models, suggesting an anti-angiogenic effect. We now report that in animals fed KetoCal® (KC)(4:1 fat:protein/carbohydrates) ad libitum, peritumoral edema is significantly reduced early in tumor progression when compared to those fed a standard rodent diet. Gene expression profiling demonstrated that KC decreases the expression of the gene encoding vascular endothelial growth factor B (VEGFB) and angiopoetin 1 receptor (TEK). Furthermore, protein analysis showed a reduction of platelet endothelial cell adhesion molecule 1 (PECAM1/CD31) in tumors from animals maintained on KC. Taken together our data suggests that KC alters the angiogenic processes involved in malignant progression of gliomas. A greater understanding of the effects of the ketogenic diet as an adjuvant therapy will allow for a more rational approach to its clinical use