bluuebunny/crossref_metadata_2025 huggingface dataset:
Existence and uniqueness of constrained globally optimal feedback controls in a linear‐quadratic framework
Authors: Xu Yashan
Published: August 2006

A constrained closed‐loop optimal control problem is considered in
a linear‐quadratic framework. To solve the problem, a special type
open‐loop optimal control problem and a standard open‐loop optimal
control problem are introduced and carefully studied, via which
the existence and uniqueness of the globally optimal closed‐loop
control is established by a synthesis method.
Existence of solutions of a special class of fuzzy integral equations
Authors: Balachandran K. , Kanagarajan K.
Published: August 2006

We prove an existence theorem for a special class of fuzzy
integral equations involving fuzzy set‐valued mappings. The
results are obtained by using the contraction mapping principle.
Stock market dynamics created by interacting agents
Authors: Remita Mohamed Riad , Eisele Karl-Theodor
Published: August 2006

We study a stock market model, consisting in a large number of agents, going eventually to infinity, and evaluate the stock price under the influence of opinions of different agents. Next we study the behavior of prices when the market is very nervous; there appear discontinuities (phase transitions) which can be interpreted as stock market crashes.
Targeted Delivery of siRNA
Authors: Oliveira Sabrina , Storm Gert , Schiffelers Raymond M.
Published: August 2006

Therapeutic application of siRNA requires delivery to the correct
intracellular location, to interact with the RNAi machinery within the
target cell, within the target tissue responsible for the pathology. Each of
these levels of targeting poses a significant barrier. To overcome these
barriers several strategies have been developed, such as chemical
modifications of siRNA, viral nucleic acid delivery systems, and nonviral
nucleic acid delivery systems. Here, we discuss progress that has been made
to improve targeted delivery of siRNA in vivo for each of these strategies.
Screening Pesticides for Neuropathogenicity
Authors: Doherty John D.
Published: August 2006

Pesticides are routinely screened in studies that follow specific
guidelines for possible neuropathogenicity in laboratory animals.
These tests will detect chemicals that are by themselves strong
inducers of neuropathogenesis if the tested strain is susceptible
relative to the time of administration and methodology of
assessment. Organophosphate induced delayed neuropathy (OPIDN) is
the only known human neurodegenerative disease associated with
pesticides and the existing study guidelines with hens are a
standard for predicting the potential for organophosphates to
cause OPIDN. Although recent data have led to the suggestion that
pesticides may be risk factors for Parkinsonism syndrome, there
are no specific protocols to evaluate this syndrome in the
existing study guidelines. Ideally additional animal models for
human neurodegenerative diseases need to be developed and
incorporated into the guidelines to further assure the public that
limited exposure to pesticides is not a risk factor for
neurodegenerative diseases.
Computational Prediction of MicroRNAs Encoded in Viral and Other Genomes
Authors: Thomassen Gard O. S. , Røsok Øystein , Rognes Torbjørn
Published: August 2006

We present an overview of selected computational methods for
microRNA prediction. It is especially aimed at viral miRNA
detection. As the number of microRNAs increases and the range of
genomes encoding miRNAs expands, it seems that these small
regulators have a more important role than has been previously
thought. Most microRNAs have been detected by cloning and Northern
blotting, but experimental methods are biased towards abundant
microRNAs as well as being time‐consuming. Computational detection
methods must therefore be refined to serve as a faster, better,
and more affordable method for microRNA detection. We also present
data from a small study investigating the problems of
computational miRNA prediction. Our findings suggest that the
prediction of microRNA precursor candidates is fairly easy, while
excluding false positives as well as exact prediction of the
mature microRNA is hard. Finally, we discuss possible improvements
to computational microRNA detection.
Constrained control and rate or increment for linear systems with additive disturbances
Authors: Mesquine Fouad , Tadeo Fernando , Benzaouia Abdellah
Published: August 2006

This paper is devoted to the control of linear systems with
constrained control and rate or increment with additive bounded
disturbances. Necessary and sufficient conditions such that the
system evolution respects rate or increment constraints are used
to derive stabilizing feedback control. The control law respects
both constraints on control and its rate or increment and is
robust against additive bounded disturbances. An application to a
surface mount robot, where the Y‐axis of the machine uses a
typical ball screw transmission driven by a DC motor to position
circuits boards, is achieved.
Heparanase: A New Metastasis-Associated Antigen Recognized in Breast Cancer Patients by Spontaneously Induced Memory T Lymphocytes
Authors: Sommerfeldt Nora , Beckhove Philipp , Ge Yingzi , Schütz Florian , Choi Carmen , Bucur Mariana , Domschke Christoph , Sohn Christof , Schneeweis Andreas , Rom Joachim , Pollmann Dirk , Leucht Dagmar , Vlodavsky Israel , Schirrmacher Volker
Published: August 2006

Increased expression and secretion of heparanase (Hpa) by tumor cells promotes tumor invasion through extracellular matrices, tissue destruction, angiogenesis, and metastasis. Here, we show the existence in breast cancer patients of Hpa-specific T lymphocytes by fluorescence-activated cell sorting flow cytometry using Hpa peptide-MHC class I tetramers. We furthermore show memory T-cell responses in a high proportion of breast cancer patients to Hpa-derived HLA-A2-restricted peptides, leading to production of IFN-γ and to generation of antitumor CTLs lysing breast cancer cells. Such CTLs recognized endogenously processed respective Hpa peptides on Hpa-transfected and Hpa-expressing untransfected breast carcinoma cells. According to these results and to the fact that such cells were not found in healthy people, Hpa seems to be an attractive new tumor-associated antigen and its HLA-A2-restricted peptides ought to be good candidates for peptide vaccination to reactivate memory immune responses to invasive and metastatic cancer cells. (Cancer Res 2006; 66(15): 7716-23)
Combined Effect of Proteasome and Calpain Inhibition on Cisplatin-Resistant Human Melanoma Cells
Authors: Młynarczuk-Biały Izabela , Roeckmann Heike , Kuckelkorn Ulrike , Schmidt Boris , Umbreen Sumaira , Gołąb Jakub , Ludwig Antje , Montag Christina , Wiebusch Lüder , Hagemeier Christian , Schadendorf Dirk , Kloetzel Peter-M. , Seifert Ulrike
Published: August 2006

Resistance of tumor cells to cisplatin is a common feature frequently encountered during chemotherapy against melanoma caused by various known and unknown mechanisms. To overcome drug resistance toward cisplatin, a targeted treatment using alternative agents, such as proteasome inhibitors, has been investigated. This combination could offer a new therapeutic approach. Here, we report the biological effects of proteasome inhibitors on the parental cisplatin-sensitive MeWo human melanoma cell line and its cisplatin-resistant MeWocis1 variant. Our experiments show that proteasome inhibitor treatment of both cell lines impairs cell viability at concentrations that are not toxic to primary human fibroblasts in vitro. However, compared with the parental MeWo cell line, significantly higher concentrations of proteasome inhibitor are required to reduce cell viability of MeWocis1 cells. Moreover, whereas proteasome activity was inhibited to the same extent in both cell lines, IκBα degradation and nuclear factor-κB (NF-κB) activation in MeWocis1 cells was proteasome inhibitor independent but essentially calpain inhibitor sensitive. In support, a calpain-specific inhibitor impaired NF-κB activation in MeWocis1 cells. Here, we show that cisplatin resistance in MeWocis1 is accompanied by a change in the NF-κB activation pathway in favor of calpain-mediated IκBα degradation. Furthermore, combined exposure to proteasome and calpain inhibitor resulted in additive effects and a strongly reduced cell viability of MeWocis1 cells. Thus, combined strategies targeting distinct proteolytic pathways may help to overcome mechanisms of drug resistance in tumor cells. (Cancer Res 2006; 66(15): 7598-605)
Helicobacter pylori Can Induce Heparin-Binding Epidermal Growth Factor Expression via Gastrin and Its Receptor
Authors: Dickson Jacqueline H. , Grabowska Anna , El-Zaatari Mohamad , Atherton John , Watson Susan A.
Published: August 2006

Both gastrin and Helicobacter pylori have been shown capable of up-regulating gene expression and protein shedding of heparin-binding epidermal growth factor (HB-EGF). Furthermore, the bacteria have previously been shown to induce serum hypergastrinemia in infected individuals. The aim of this work was to assess the extent to which the ability of H. pylori to up-regulate expression of HB-EGF can be attributed to its effect on gastrin. Gastric cells, transfected with either gastrin small interfering RNA or antisense plasmid or the gastrin/cholecystokinin-2 receptor (CCK-2R), were cultured for 24 hours with H. pylori+/−, a CCK-2R antagonist. Gene expression levels were measured using reverse transcription-PCR, whereas protein changes were measured using ELISA, Western blotting, and immunofluorescence. H. pylori induced significantly higher levels of HB-EGF gene expression and ectodomain shedding in the CCK-2R-transfected cells than the vector control (P < 0.01). Addition of the CCK-2R inhibitor significantly decreased gene and shedding up-regulation. Gastrin down-regulation reduced the effect of the bacteria on HB-EGF gene and protein expression levels. Endogenous gastrin and CCK-2R expression were also found to be significantly up-regulated in all cell lines as a result of exposure to H. pylori (P < 0.02). Gastric mucosal tissue from H. pylori–infected individuals had significantly higher CCK-2R expression levels than noninfected (P < 0.003), and in hypergastrinemic mice, there was an increase in HB-EGF-expressing cells in the gastric mucosa and colocalization of HB-EGF with CCK-2R-positive enterochromaffin-like cells. In conclusion, gastrin and the CCK-2R play significant roles in the induction of HB-EGF gene and protein expression and ectodomain shedding by H. pylori. (Cancer Res 2006; 66(15): 7524-31)
Inhibitory Effects of B Cells on Antitumor Immunity
Authors: Inoue Satoshi , Leitner Wolfgang W. , Golding Basil , Scott Dorothy
Published: August 2006

B-cell functions in antitumor immunity are not well understood. In this study, we evaluated the role of B cells in the development of antitumor immunity using Friend murine leukemia virus gag-expressing mouse EL-4 (EL-4 gag), D5 mouse melanoma, or MCA304 mouse sarcoma cells. To screen tumors for susceptibility to B-cell-deficient immune environments, spleen cells from naive C57BL/6 [wild-type (WT)] and B-cell knockout (BKO) mice were cultured with irradiated tumor cells in vitro. When cells were stimulated with EL-4 gag or D5 (but not MCA304 tumors), IFN-γ production from CD8 T cells and natural killer cells was markedly decreased in WT compared with BKO cultures. IFN-γ production was correlated with CD40 ligand expression on the tumor and inversely with interleukin-10 (IL-10) production by B cells. Sorted WT B cells produced more IL-10 than CD40 knockout (CD40KO) B cells when cocultured with EL-4 gag or D5 (but not MCA304). IFN-γ production by BKO cells was reduced by the addition of sorted naive WT B cells (partially by CD40KO B cells) or recombinant mouse IL-10. In vivo tumor progression mirrored in vitro studies in that WT mice were unable to control tumor growth whereas EL-4 gag and D5 tumors (but not MCA304) were eliminated in BKO mice. Robust in vivo antitumor CTLs developed only in BKO tumor-challenged mice. Our studies provide the first mechanistic basis for the concept that B-cell depletion could therapeutically enhance antitumor immune responses to certain tumors by decreasing IL-10 production from B cells. (Cancer Res 2006; 66(15): 7741-7)
Tumor-Derived Matrix Metalloproteinase-1 Targets Endothelial Proteinase-Activated Receptor 1 Promoting Endothelial Cell Activation
Authors: Goerge Tobias , Barg Alexej , Schnaeker Eva-Maria , Poppelmann Birgit , Shpacovitch Victoria , Rattenholl Anke , Maaser Christian , Luger Thomas A. , Steinhoff Martin , Schneider Stefan W.
Published: August 2006

In the vascular system, circulating tumor cells interact with endothelial cells. Tumor-endothelial cross-talk transforms the intravascular milieu to a prothrombotic, proinflammatory, and cell-adhesive state called endothelial cell activation (ECA). In the present study, we analyze the potential of metastatic tumor-derived soluble factors to transform the vascular endothelium into a prothrombotic and proinflammatory activated state. Supernatant from cultured melanoma and colon cancer cells (A375, WM9, A7, and HT-29) induced an acute activation of macrovascular and microvascular endothelial cells (human umbilical vein endothelial cells and human dermal microvascular endothelial cells) as shown by intracellular calcium flux and secretion of von Willebrand factor and interleukin-8, all markers of acute ECA. This process was inhibited using specific proteinase-activated receptor 1 (PAR1) inhibitors (RWJ-58259 and SCH-79797), indicating a mediating role for endothelial thrombin receptors. Immunofluorescence, Western blot analysis, and collagenase activity assay of tumor cells and culture supernatant revealed the presence of matrix metalloproteinase-1 (MMP-1), a recently described activator of PAR1. Inhibition of MMP-1 in supernatant from cultured tumor cells significantly attenuated ECA. Additional studies using isolated human MMP-1 (5 nmol/L) proved the presence of a functional MMP-1/PAR1 axis in tumor-endothelial communication. These findings show a new pathway of tumor-endothelial cross-talk via an intravascular MMP1/PAR1 axis in microvascular and macrovascular endothelium. Inhibition of this cross-talk may be a powerful means to prevent tumor-induced ECA and thus thrombotic and inflammatory cell adhesion. (Cancer Res 2006; 66(15): 7766-74)
c-Abl Expression in Chronic Lymphocytic Leukemia Cells: Clinical and Therapeutic Implications
Authors: Lin Ke , Glenn Mark A. , Harris Robert J. , Duckworth Andrew D. , Dennett Sally , Cawley John C. , Zuzel Mirko , Slupsky Joseph R.
Published: August 2006

c-Abl is important for normal B-cell development, but little is known about the function of this nonreceptor tyrosine kinase in chronic lymphocytic leukemia (CLL). Therefore, the aim of the present study was to examine the clinical, therapeutic, and pathogenetic importance of c-Abl in this disease. We show that the malignant cells of CLL predominantly express the type 1b splice variant of c-Abl and that the expression of c-Abl protein is higher in CLL cells than in normal peripheral blood B cells. Moreover, we show that the levels of c-Abl protein expression correlate positively with tumor burden and disease stage, and negatively with IgVH mutation. We also show that STI-571, an inhibitor of c-Abl kinase activity, induces apoptosis of CLL cells with high c-Abl expression levels through a mechanism involving inhibition of nuclear factor κB. We conclude that overexpression of c-Abl is likely to play a pathogenetic role in CLL and that STI-571 may be of potential use in the treatment of this disease. (Cancer Res 2006; 66(15): 7801-9)
Epigenomic Profiling Reveals Novel and Frequent Targets of Aberrant DNA Methylation-Mediated Silencing in Malignant Glioma
Authors: Kim Tae-You , Zhong Sheng , Fields C. Robert , Kim Jeong Hoon , Robertson Keith D.
Published: August 2006

Malignant glioma is the most common central nervous system tumor of adults and is associated with a significant degree of morbidity and mortality. Gliomas are highly invasive and respond poorly to conventional treatments. Gliomas, like other tumor types, arise from a complex and poorly understood sequence of genetic and epigenetic alterations. Epigenetic alterations leading to gene silencing, in the form of aberrant CpG island promoter hypermethylation and histone deacetylation, have not been thoroughly investigated in brain tumors, and elucidating such changes is likely to enhance our understanding of their etiology and provide new treatment options. We used a combined approach of pharmacologic inhibition of DNA methylation and histone deacetylation, coupled with expression microarrays, to identify novel targets of epigenetic silencing in glioma cell lines. From this analysis, we identified >160 genes up-regulated by 5-aza-2′-deoxycytidine and trichostatin A treatment. Further characterization of 10 of these genes, including the putative metastasis suppressor CST6, the apoptosis-inducer BIK, and TSPYL5, whose function is unknown, revealed that they are frequent targets of epigenetic silencing in glioma cell lines and primary tumors and suppress glioma cell growth in culture. Furthermore, we show that other members of the TSPYL gene family are epigenetically silenced in gliomas and dissect the contribution of individual DNA methyltransferases to the aberrant promoter hypermethylation events. These studies, therefore, lay the foundation for a comprehensive understanding of the full extent of epigenetic changes in gliomas and how they may be exploited for therapeutic purposes. (Cancer Res 2006; 66(15): 7490-501)
p38γ Mitogen-Activated Protein Kinase Integrates Signaling Crosstalk between Ras and Estrogen Receptor to Increase Breast Cancer Invasion
Authors: Qi Xiaomei , Tang Jun , Loesch Mathew , Pohl Nicole , Alkan Serhan , Chen Guan
Published: August 2006

Ras is believed to stimulate invasion and growth by different effector pathways, and yet, the existence of such effectors under physiologic conditions has not been shown. Estrogen receptor (ER), on the other hand, is both anti-invasive and proliferative in human breast cancer, with mechanisms for these paradoxical actions remaining largely unknown. Our previous work showed an essential role of p38γ mitogen-activated protein kinase in Ras transformation in rat intestinal epithelial cells, and here, we show that p38γ integrates invasive antagonism between Ras and ER to increase human breast cancer invasion without affecting their proliferative activity. Ras positively regulates p38γ expression, and p38γ in turn mediates Ras nonmitogenic signaling to increase invasion. Expression of the Ras/p38γ axis, however, is trans-suppressed by ER that inhibits invasion and stimulates growth also by distinct mechanisms. Analysis of ER and its cytoplasmic localized mutant reveals that ER additionally binds to p38γ protein, leading to its specific down-regulation in the nuclear compartment. A p38γ-antagonistic activity of ER was further shown in a panel of breast cancer cell lines and was shown independent of estrogens by both ER depletion and ER expression. These results revealed that both Ras and ER use distinct pathways to regulate breast cancer growth and invasion, and that p38γ specifically integrates their antagonistic activity to stimulate cell invasion. Selective targeting of p38γ-dependent invasion pathways may be a novel strategy to control breast cancer progression. (Cancer Res 2006; 66(15): 7540-7)
Mitochondrial DNA Mutations and Apoptosis in Mammalian Aging
Authors: Kujoth Gregory C. , Leeuwenburgh Christiaan , Prolla Tomas A.
Published: August 2006

Mutations in mitochondrial DNA (mtDNA) accumulate during aging, but their significance to longevity and age-associated disease has been uncertain. Recently, in support of the hypothesis that mtDNA integrity is important, we have shown that age-associated diseases arise more rapidly in mice where mtDNA mutations and increased levels of apoptosis occur at higher rates than normal due to expression of an error-prone mtDNA polymerase. Further studies in this model may provide deeper insights into the relationship between mitochondria, aging, and susceptibility to age-associated diseases, such as cancer. (Cancer Res 2006; 66(15): 7386-9)
Myopodin-Mediated Suppression of Prostate Cancer Cell Migration Involves Interaction with Zyxin
Authors: Yu Yan Ping , Luo Jian-Hua
Published: August 2006

Myopodin was identified as a tumor suppressor gene that is frequently deleted in aggressive prostate cancer. Expression of myopodin protein suppresses both tumor growth and metastasis in vitro and in vivo. In the present study employing a yeast two-hybrid system, we found that zyxin, a molecule known to regulate cell motility and migration, binds with myopodin with high affinity. The binding between zyxin and myopodin seems to be direct. Screening of a series of myopodin deletion mutants and peptide competition analyses revealed that myopodin is bound by zyxin at a site located within the sequence of the 19 amino acids at the myopodin COOH terminus. Importantly, this is the same region where the tumor suppressor activity of myopodin is located. The motility and invasion suppression activity of myopodin were significantly weakened in myopodin mutants lacking this sequence. Thus, our studies suggest that zyxin may be a critical functional regulator of myopodin. (Cancer Res 2006; 66(15): 7414-9)
Epigenetic Inactivation of the Dioxin-Responsive Cytochrome P4501A1 Gene in Human Prostate Cancer
Authors: Okino Steven T. , Pookot Deepa , Li Long-Cheng , Zhao Hong , Urakami Shinji , Shiina Hiroaki , Igawa Mikio , Dahiya Rajvir
Published: August 2006

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD; dioxin) is a toxic environmental contaminant that works through dioxin response elements (DRE) to activate gene expression. We tested the hypothesis that cancer-related epigenetic changes suppress dioxin activation of the cytochrome P4501A1 (CYP1A1) gene. 5-Aza-2′-deoxycytidine (5-aza-CdR), an inhibitor of DNA methylation, increases TCDD-inducible CYP1A1 mRNA expression in cancerous LNCaP cells but not in noncancerous PWR-1E and RWPE-1 cells (all human prostate cell lines). Bisulfite DNA sequencing shows that the TCDD-responsive CYP1A1 enhancer is highly methylated in LNCaP cells but not in RWPE-1 cells. In vivo footprinting experiments reveal that unmethylated DRE sites do not bind protein in response to TCDD in LNCaP cells, whereas inducible DRE occupancy occurs in RWPE-1 cells. Pretreatment of LNCaP cells with 5-aza-CdR partially restores TCDD-inducible DRE occupancy, showing that DNA methylation indirectly suppresses DRE occupancy. Chromatin immunoprecipitation experiments reveal that LNCaP cells lack trimethyl histone H3 lysine 4, a mark of active genes, on the CYP1A1 regulatory region, whereas this histone modification is prevalent in PWR-1E and RWPE-1 cells. We also analyzed CYP1A1 enhancer methylation in human prostate tissue DNA. We do not detect CYP1A1 enhancer methylation in 30 DNA samples isolated from noncancerous prostate tissue. In contrast, 11 of 30 prostate tumor DNA samples have detectable CYP1A1 enhancer methylation, indicating that it is hypermethylated in prostate tumors. This is the first report that shows that CYP1A1 is aberrantly hypermethylated in human prostate cancer and has an altered, inaccessible chromatin structure that suppresses its dioxin responsiveness. (Cancer Res 2006; 66(15): 7420-8) (Cancer Res 2006; 66(15): 7420-8)
Innate Immune Inflammatory Response against Enteric Bacteria Helicobacter hepaticus Induces Mammary Adenocarcinoma in Mice
Authors: Rao Varada P. , Poutahidis Theofilos , Ge Zhongming , Nambiar Prashant R. , Boussahmain Chakib , Wang Yan Yan , Horwitz Bruce H. , Fox James G. , Erdman Susan E.
Published: August 2006

Inflammation associated with bacterial infections is a risk factor for cancers in humans, yet its role in breast cancer remains poorly understood. We have previously shown that innate immune inflammatory response against intestinal bacteria is sufficient to induce colon cancer. Here we report that infecting Rag2-deficient C57BL/6 ApcMin/+ mice with an intestinal bacterial pathogen, Helicobacter hepaticus, significantly promotes mammary carcinoma in females and enhances intestinal adenoma multiplicity by a tumor necrosis factor α (TNFα)–dependent mechanism. The mammary and intestinal tumor development as well as the increase in proinflammatory mediators is suppressed by adoptive transfer of interleukin 10–competent CD4+CD45RBloCD25+ regulatory (TR) cells. Furthermore, prior exposure of donor mice to H. hepaticus significantly enhances antitumor potency of their TR cells. Interestingly, these microbially experienced TR cells suppress tumorigenesis more effectively in recipient mice irrespective of their tumor etiology. These data suggest that infections with enteric pathogens enhance TR-cell potency and protect against epithelial cancers later in life, potentially explaining paradoxical increases in cancer risk in developed countries having more stringent hygiene practices. The possibility that dysregulated gut microbial infections in humans may lead to cancer in anatomically distant organs, such as breast, highlights the need for novel immune-based strategies in cancer prevention and treatment. (Cancer Res 2006;66(15):7395-400)
A Novel Orally Active Small Molecule Potently Induces G1 Arrest in Primary Myeloma Cells and Prevents Tumor Growth by Specific Inhibition of Cyclin-Dependent Kinase 4/6
Authors: Baughn Linda B. , Di Liberto Maurizio , Wu Kaida , Toogood Peter L. , Louie Tracey , Gottschalk Rachel , Niesvizky Ruben , Cho Hearn , Ely Scott , Moore Malcolm A.S. , Chen-Kiang Selina
Published: August 2006

Cell cycle deregulation is central to the initiation and fatality of multiple myeloma, the second most common hematopoietic cancer, although impaired apoptosis plays a critical role in the accumulation of myeloma cells in the bone marrow. The mechanism for intermittent, unrestrained proliferation of myeloma cells is unknown, but mutually exclusive activation of cyclin-dependent kinase 4 (Cdk4)-cyclin D1 or Cdk6-cyclin D2 precedes proliferation of bone marrow myeloma cells in vivo. Here, we show that by specific inhibition of Cdk4/6, the orally active small-molecule PD 0332991 potently induces G1 arrest in primary bone marrow myeloma cells ex vivo and prevents tumor growth in disseminated human myeloma xenografts. PD 0332991 inhibits Cdk4/6 proportional to the cycling status of the cells independent of cellular transformation and acts in concert with the physiologic Cdk4/6 inhibitor p18INK4c. Inhibition of Cdk4/6 by PD 0332991 is not accompanied by induction of apoptosis. However, when used in combination with a second agent, such as dexamethasone, PD 0332991 markedly enhances the killing of myeloma cells by dexamethasone. PD 0332991, therefore, represents the first promising and specific inhibitor for therapeutic targeting of Cdk4/6 in multiple myeloma and possibly other B-cell cancers. (Cancer Res 2006; 66(15): 7661-7)
PIK3CA Mutations Are an Early Genetic Alteration Associated with FGFR3 Mutations in Superficial Papillary Bladder Tumors
Authors: López-Knowles Elena , Hernández Silvia , Malats Núria , Kogevinas Manolis , Lloreta Josep , Carrato Alfredo , Tardón Adonina , Serra Consol , Real Francisco X. ,   EPICURO Study Group Investigators
Published: August 2006

Bladder tumors constitute a very heterogeneous disease. Superficial tumors are characterized by a high prevalence of FGFR3 mutations and chromosome 9 alterations. High-grade and muscle-invasive tumors are characterized by Tp53 mutations and aneuploidy. We have analyzed the sequence of exons 9 and 20 of PIK3CA in a panel of bladder tumors covering the whole spectrum of the disease. DNA from formalin-fixed, paraffin-embedded tumor sections was amplified by PCR and products were sequenced. In an unselected panel of tumors representative of the disease, the PIK3CA mutation prevalence was 13% (11 of 87). Mutations occurred mainly at the previously identified hotspots (codons 542, 545, 1007, and 1047). The distribution according to stage was as follows: papillary urothelial neoplasms of uncertain malignant potential (PUNLMP; 11 of 43, 25.6%), Ta (9 of 57, 16%), T1 (2 of 10, 20%), and muscle-invasive tumors (0 of 20, 0%; P = 0.019). Mutations were associated with low-grade tumors: grade 1 (6 of 27, 22.2%), grade 2 (3 of 23, 13%), and grade 3 (2 of 37, 5.4%; P = 0.047). Overall, PIK3CA mutations were strongly associated with FGFR3 mutations: 18 of 69 (26%) FGFR3mut tumors were PIK3CAmut, versus 4 of 58 (6.9%) FGFR3wt tumors (P = 0.005). Our findings indicate that PIK3CA mutations are a common event that can occur early in bladder carcinogenesis and support the notion that papillary and muscle-invasive tumors arise through different molecular pathways. PIK3CA may constitute a novel diagnostic and prognostic tool, as well as a therapeutic target, in bladder cancer. (Cancer Res 2006; 66(15): 7401-4)
ROS Fusion Tyrosine Kinase Activates a SH2 Domain–Containing Phosphatase-2/Phosphatidylinositol 3-Kinase/Mammalian Target of Rapamycin Signaling Axis to Form Glioblastoma in Mice
Authors: Charest Al , Wilker Erik W. , McLaughlin Margaret E. , Lane Keara , Gowda Ram , Coven Shanie , McMahon Kevin , Kovach Steven , Feng Yun , Yaffe Michael B. , Jacks Tyler , Housman David
Published: August 2006

Glioblastoma multiforme is the most common and lethal form of primary brain cancer. Diagnosis of this advanced glioma has a poor prognosis due to the ineffectiveness of current therapies. Aberrant expression of receptor tyrosine kinases (RTK) in glioblastoma multiformes is suggestive of their role in initiation and maintenance of these tumors of the central nervous system. In fact, ectopic expression of the orphan RTK ROS is a frequent event in human brain cancers, yet the pathologic significance of this expression remains undetermined. Here, we show that a glioblastoma-associated, ligand-independent rearrangement product of ROS (FIG-ROS) cooperates with loss of the tumor suppressor gene locus Ink4a;Arf to produce glioblastomas in the mouse. We show that this FIG-ROS-mediated tumor formation in vivo parallels the activation of the tyrosine phosphatase SH2 domain–containing phosphatase-2 (SHP-2) and a phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin signaling axis in tumors and tumor-derived cell lines. We have established a fully penetrant preclinical model for adult onset of glioblastoma multiforme in keeping with major genetic events observed in the human disease. These findings provide novel and important insights into the role of ROS and SHP-2 function in solid tumor biology and set the stage for preclinical testing of targeted therapeutic approaches. (Cancer Res 2006; 66(15): 7473-81)
Roles of Adenosine Receptor Subtypes in the Antinociceptive Effect of Intrathecal Adenosine in a Rat Formalin Test
Authors: Yoon Myung Ha , Bae Hong Beom , Choi Jeong Il , Kim Seok Jai , Chung Sung Tae , Kim Chang Mo
Published: August 2006

The contributions of adenosine receptor subtypes to antinociception produced by adenosine were determined at the spinal level. There are 4 types of adenosine receptors, namely A1, A2A, A2B and A3. The authors investigated the properties of the subtypes of spinal adenosine receptors in terms of nociceptive modulation. The nociceptive state was induced by subcutaneously injecting formalin solution (5%, 50 µl) into the hind paws of male Sprague-Dawley rats. After observing the effect of intrathecal adenosine during the formalin test, the effects of intrathecal adenosine A1 (CPT), A2A (CSC), A2B (alloxazine) and A3 (MRS 1220) receptor antagonists on the action of adenosine were examined. Intrathecal adenosine inhibited phase 2 flinching response without affecting phase 1 response. CPT, CSC, alloxazine and MRS 1220 antagonized the antinociceptive action of adenosine during phase 2 of the formalin test. These results suggest that spinal adenosine A1, A2A, A2B and A3 receptors may play an important role in the antinociception of adenosine in the formalin-induced facilitated state.
Role of Peritubular Capillary Loss and Hypoxia in Progressive Tubulointerstitial Fibrosis in a Rat Model of Aristolochic Acid Nephropathy
Authors: Sun Dong , Feng Jiangmin , Dai Chun , Sun Li , Jin Tao , Ma Jianfei , Wang Lining
Published: August 2006

Background/Aims: To investigate the effects of peritubular capillary (PTC) loss and hypoxia on the progression of tubulointerstitial fibrosis in a rat model of aristolochic acid nephropathy (AAN). Methods: Female Wistar rats received Caulis aristolochiae manshuriensis (CAM) decoction by gavage for 8 weeks, and were sacrificed at 8, 12 and 16 weeks, respectively, after administration. Blood urea nitrogen (BUN), serum creatinine (Scr) and urinary protein were monitored prior to sacrifice. PTC loss and tubulointerstitial hypoxia were assessed by CD34 immunostaining and hypoxia-inducible factor-α subunit 1 (HIF-1α) expression, respectively. Myofibroblasts were assessed by α-smooth muscle actin (α-SMA) expression. The expression of angiogenic factor was assessed by vascular endothelial growth factor (VEGF). Results: AAN rats differed from controls by increased BUN, Scr and 24-hour urinary protein excretion rates. There was a progressive loss of PTCs in the AAN model, which was associated with the decreased expression of VEGF. A significant increase in nuclear localization of HIF-1α was seen 16 weeks after treatment with CAM decoction in the context of severe tubulointerstitial damage. Multifocal tubulointerstitial fibrosis was seen in AAN rats at weeks 12 and 16, predominantly in the area of the outer stripe and outer medulla. No significant pathologic changes were found in control rats. Conclusion: Following the reduction of PTCs density and up-regulation of HIF-1α, the tubulointerstitial fibrosis area increased. Ischemia and hypoxia are the important causes of severe tubulointerstitial fibrosis in AAN rats.
Embryonic Stem Cell-Derived Endothelial Cells May Lack Complete Functional Maturation in vitro
Authors: McCloskey Kara E. , Smith Debra A. , Jo Hanjoong , Nerem Robert M.
Published: August 2006

Stem cell therapies will only become clinically relevant if the stem cells differentiated in vitro function as their in vivo counterparts. Here, we employed our previously developed techniques for deriving endothelial cells (>96% purity) from mouse embryonic stem cells (ESC) and compared these with mouse aortic endothelial cells (MAEC) obtained from thoracic aortas. Immunocytochemical analysis of ESC-derived endothelial cells (EC) demonstrates that both cell types are positive for the EC markers endothelial nitric oxide synthase (eNOS), Flk-1, Flt-1, vascular endothelial cadherin (VEcad), platelet-endothelial cell adhesion molecule-1 (PECAM-1), and CD34. However, ESC-derived EC express slightly lower levels of PECAM-1 and VE-cadherin, and significantly lower levels of acetylated low-density lipoprotein (LDL) uptake and von Willebrand factor. Although ESC-derived EC do express VE-cadherin, the VE-cadherin in the ESC-derived EC did not localize as well at the cell-cell junctions as in the MAEC. Interestingly, ESC-derived EC express much greater levels of the endothelial and hematopoietic stem cell marker CD34 and vasculogenic and angiogenic sprouting than MAEC. These results indicate that ESC-derived EC share some key characteristics of ‘mature’ EC, while retaining markers of alternate phenotypes including immature endothelium.
Importance of the Electrocardiographic Strain Pattern in Patients With Resistant Hypertension
Authors: Salles Gil , Cardoso Claudia , Nogueira Armando R. , Bloch Katia , Muxfeldt Elizabeth
Published: August 2006

The electrocardiographic strain pattern is a marker of left ventricular hypertrophy and adverse cardiovascular prognosis. The objective of this study was to assess the factors associated with the presence of ECG strain in patients with resistant hypertension and, specifically, to evaluate the relationships between strain and left ventricular mass (LVM) and structure. In a cross-sectional design, 440 resistant hypertensive subjects were evaluated. Clinical, laboratory, electrocardiographic, 24-hour ambulatory blood pressures, and echocardiographic variables were obtained. Statistical analysis involved bivariate tests, analysis of covariance, and multivariate logistic regression. An ECG strain pattern was present in 101 patients (23%). Patients with strain were more frequently men with lower body mass index, had more target-organ damage, higher 24-hour blood pressure, higher serum creatinine and 24-hour microalbuminuria, and more prolonged QT interval duration than those without strain. After controlling for all covariates, the presence of strain remained associated with increased LVM and wall thicknesses, both in all patients and also in those with echocardiographic left ventricular hypertrophy. Furthermore, the presence of ECG strain was associated with increased LVM (
P
<0.001), higher 24-hour systolic blood pressure (
P
<0.001), prolonged maximum QTc-interval duration (
P
<0.001), lower waist circumference (
P
=0.009), male gender (
P
=0.011), physical inactivity (
P
=0.020), higher serum creatinine (
P
=0.031) and fasting glycemia (
P
=0.027), and the presence of coronary heart disease (
P
=0.001) and peripheral arterial disease (
P
=0.045). Thus, in resistant hypertension patients, the presence of ECG strain is independently associated with increased left ventricular wall thicknesses and mass and also with other potentially adverse factors. These relationships offer insight into the known association between strain and unfavorable cardiovascular prognosis.
Pharmacological- and Gene Therapy-Based Inhibition of Protein Kinase Cα/β Enhances Cardiac Contractility and Attenuates Heart Failure
Authors: Hambleton Michael , Hahn Harvey , Pleger Sven T. , Kuhn Matthew C. , Klevitsky Raisa , Carr Andrew N. , Kimball Thomas F. , Hewett Timothy E. , Dorn Gerald W. , Koch Walter J. , Molkentin Jeffery D.
Published: August 2006

Background—

The conventional protein kinase C (PKC) isoform α functions as a proximal regulator of Ca
2+
handling in cardiac myocytes. Deletion of PKCα in the mouse results in augmented sarcoplasmic reticulum Ca
2+
loading, enhanced Ca
2+
transients, and augmented contractility, whereas overexpression of PKCα in the heart blunts contractility. Mechanistically, PKCα directly regulates Ca
2+
handling by altering the phosphorylation status of inhibitor-1, which in turn suppresses protein phosphatase-1 activity, thus modulating phospholamban activity and secondarily, the sarcoplasmic reticulum Ca
2+
ATPase.

Methods and Results—

In the present study, we show that short-term inhibition of the conventional PKC isoforms with Ro-32-0432 or Ro-31-8220 significantly augmented cardiac contractility in vivo or in an isolated work-performing heart preparation in wild-type mice but not in
PKCα
-deficient mice. Ro-32-0432 also increased cardiac contractility in 2 different models of heart failure in vivo. Short-term or long-term treatment with Ro-31-8220 in a mouse model of heart failure due to deletion of the
muscle lim protein
gene significantly augmented cardiac contractility and restored pump function. Moreover, adenovirus-mediated gene therapy with a dominant-negative PKCα cDNA rescued heart failure in a rat model of postinfarction cardiomyopathy. PKCα was also determined to be the dominant conventional PKC isoform expressed in the adult human heart, providing potential relevance of these findings to human pathophysiology.

Conclusions—

Pharmacological inhibition of PKCα, or the conventional isoforms in general, may serve as a novel therapeutic strategy for enhancing cardiac contractility in certain stages of heart failure.
Atrioventricular Ring Reentry in Embryonic Mouse Hearts
Authors: Valderrábano Miguel , Chen Fuhua , Dave Amish S. , Lamp Scott T. , Klitzner Thomas S. , Weiss James N.
Published: August 2006

Background—

During development, AV conduction switches from base-to-apex to apex-to-base conduction after emergence of the conduction system. We hypothesize that after this transition, the bulk of the AV ring, although no longer required for AV conduction, remains transiently able to conduct, providing a potential arrhythmia substrate. We studied AV conduction during this transition and its sensitivity to autonomic modulation.

Methods and Results—

Simultaneous voltage and Ca
2+
mapping with RH-237 and Rhod-2 was performed with 2 CCD cameras in embryonic mouse hearts (n=43). Additionally, isolated calcium mapping was performed in 309 hearts with fluo-3AM. Propagation patterns in voltage and Ca
2+
mapping coincided. Arrhythmias were uncommon under basal conditions, with AV block in 14 (4%) and junctional rhythms in 4 (1%). Arrhythmias increased after stimulation with isoproterenol—junctional rhythm in 9 (3%) and ventricular rhythms in 22 (6%)—although AV block decreased (3 hearts, 1%). Adding carbachol after isoproterenol caused dissociated antegrade and retrograde AV ring conduction in 30 (8.6%) of E10.5 and E11.5 hearts, occurring preferentially in the right and left sides of the ring, respectively. In 2 cases, reentry occurred circumferentially around the AV ring, perpendicular to normal propagation. Reentry persisted for multiple beats, lasting from 3 to 22 minutes. No episodes of AV ring reentry occurred in E9.5 hearts.

Conclusions—

AV ring reentry can occur by spatial dissociation of antegrade and retrograde conduction during combined adrenergic and muscarinic receptor stimulation. Critical maturation (>E9.5) seems to be required to sustain reentry.
Comparable Wages, Inflation, and School Finance Equity
Authors: Taylor Lori L.
Published: August 2006

A ComparableWage Index (CWI) is an attractive mechanism for measuring geographic variations in the cost of education. A CWImeasures uncontrollable variations in educator pay by observing systematic variations in the earnings of comparable workers who are not educators.

Together, the 2000 census and the Occupational Employment Statistics survey support the construction of just such an index. The resulting panel of index values measures wage levels in all parts of the United States from 1997 through 2004 and reveals substantial variation in purchasing power both across school districts and across time.

Such inequalities undermine the equity and adequacy goals of school finance formulas. If states were successfully directing additional resources to school districts in high-cost environments, then measured inequality within states should fall when differences in purchasing power are taken into account. Instead, cost adjustment widens the spending gap in all but a handful of states.
Art, Prophecy, and Drama in the Choir of Salisbury Cathedral
Authors: Reeve Matthew
Published: August 2006

The former painted cycle over the vaults of Salisbury Cathedral represents one of the great losses of thirteenth-century English art. This paper focuses on the imagery over the three-bay choir, which features twentyfour Old Testament kings and prophets each holding scrolls with texts prefiguring the Coming of Christ. The content of the cycle derives from a sermon, well known in the Middle Ages, by Pseudo-Augustine: Contra Judaeos, Paganos et Arianos. Yet the most immediate sources lie in twelfth and thirteenth-century extrapolations of the Pseudo-Augustinian sermon in liturgical drama, the so-called Ordo Prophetarum, or prophet plays. This observation leads to a discussion of the relationship of imagery to its liturgical setting. It is argued that the images on the choir vaults were also to be understood allegorically as types of the cathedral canons, who originally sat in the choir stalls below. A reading of the choir as a place of prophecy is located within traditions of liturgical commentary, which allegorize processions through churches as processions through Christian history. This leads to a discussion of the allegorization of the church interior in the Gothic period.
Shadows and Illuminations: Spiritual Journeys to the Dark Side in "Young Goodman Brown" and Eyes Wide Shut
Authors: Neary John
Published: August 2006

The illuminating spiritual journey to wholeness—to "God"—can be fruitfully described as a journey into darkness. Both Christian and Buddhist writers present visions of a trek down into the valley of cares and concerns, or of a "wisdom of no escape" that gently accepts an "interesting, smelly, rich, fertile mess of stuff" to suggest the value of an encounter with darkness. This is related to Paul Tillich's call for a descent to depth, or to Michael Himes's claim that a sacramental imagination sees "what is there" in the wonderful worldly mess rather than rising above it to an ethereal mountaintop. Shadows and illuminations are not separate.Nathaniel Hawthorne's short story "Young Goodman Brown" and Stanley Kubrick's film Eyes Wide Shut are artistic depictions of such a spiritual journey to the dark side. In each case, an initially naive protagonist undergoes a dark adventure that breaks down his naiveté and forces him to confront depth, in Tillich's sense. But each digests his experience differently. The protagonist of Eyes Wide Shut gives up his stubborn certainties for a humble, uncertain, spiritually "silent" openness to the world and to his wife; the protagonist of "Young Goodman Brown," however, returns to his frozen certainties and ends up bitter and despairing. And yet, just as shadows and illuminations cannot be fully dichotomized, perhaps even these different kinds of endings are mutual supplements rather than opposites; perhaps each ending needs to be respected as a variation on the fragile human responses to a spiritual journey.
Evidence-Based Acupuncture? a Challenge Ahead
Authors: MacPherson Hugh
Published: August 2006

Acupuncture's increasingly widespread use has been paralleled by calls for more rigorous evidence of its effectiveness. In this article, some of the challenges of developing a strong evidence base are explored. As acupuncture is a complex intervention, a case is made for the appropriateness and relevance of pragmatic rather than experimental randomised controlled trials in the evaluation of acupuncture. Within this context there remain key challenges associated with ensuring treatment within a trial is sufficiently flexible, so that it can match the expected variability in patients, that outcomes measures capture the broader range of changes that can be experienced by patients, and that the therapeutic relationship is not compromised by the trial design. The central theme is the importance of protecting the integrity of the acupuncture, and the underlying principles upon which it is based.