bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of APP Synthesis and Secretion by Neuroimmunophilin Ligands and Cyclooxygenase Inhibitors
Authors: LEE ROBERT K.K. , WURTMAN RICHARD J.
Published: July 2010

Abstract:We and others previously showed that both the synthesis of the amyloid precursor protein (APP) and its processing (i.e., to amyloidogenic Aβ peptides; soluble nonamyloidogenic APPs; and other APP fragments) are regulated by neurotransmitters. Transmitters that elevate cellular cAMP levels (like norepinephrine and prostaglandins, which act on β‐adrenergic receptors and prostaglandin E2receptors respectively) enhance APP synthesis and the formation of amyloidogenic APP holoprotein. Transmitters that stimulate phosphatidylinositol hydrolysis (by activating muscarinic m1 or m3 receptors, serotoninergic 5HT2a or 5HT2c receptors, or metabotropic glutamate receptors of subtypes 1 or 5) increase the conversion of APP to soluble APPs, and decrease the formation of Aβ. These findings suggest that drugs that regulate the activity of neurotransmitter receptors might be useful in preventing the excessive formation of Aβ or other amyloid precursors in Alzheimer's disease.

We now show that neuroimmunophilin ligands (like cyclosporin A or FK‐506) and nonsteroidal antiinflammatory agents (NSAIDs), including cyclooxygenase (COX)‐2 inhibitors, can also prevent APP overexpression and the overproduction of amyloidogenic peptides. We observe that the enhancement of APP over‐expression by prostaglandin E2is inhibited by neuroimmunophilin ligands like cyclosporin A or FK‐506 (tacrolimus). We also find that the NSAIDs, which reduce prostaglandin synthesis by inhibiting COX‐1 and ‐2 enzymes, might also be expected to lower APP levels. Our present data confirm that these drugs, as well as drugs that selectively inhibit COX‐2, reduce the levels of amyloidogenic APP holoprotein in cultured neurons or in cultured astrocytes. We previously showed that elevations in cAMP, perhaps generated in response to prostaglandins, can suppress APPs secretion. The NSAIDs and COX inhibitors also increased levels of soluble APPs in the media of cultured astrocytes and neurons, perhaps acting by inhibition of prostaglandin production. Since APP holoprotein can be amyloidogenic, while APPs may be neurotrophic, our findings suggest that some neuroimmunophilin ligands, NSAIDs and COX‐2 inhibitors might suppress amyloid formation and enhance neuronal regeneration in Alzheimer's disease.
Prevention and Reduction of AD‐type Pathology in PDAPP Mice Immunized with Aβ1–42
Authors: GAMES DORA , BARD FREDERIQUE , GRAJEDA HENRY , GUIDO TERRY , KHAN KAREN , SORIANO FERDIE , VASQUEZ NICKI , WEHNER NANCY , JOHNSON‐WOOD KELLY , YEDNOCK TED , SEUBERT PETER , SCHENK DALE
Published: July 2010

Abstract: In AD certain brain structures contain a pathological density of Aβ protein deposited into plaques. The effect of genetic mutations found in early onset AD patients was an overproduction of Aβ42, strongly suggesting that overproduction of Aβ42 is associated with AD. We hypothesized that an immunological response to Aβ42 might alter its turnover and metabolism. Young PDAPP transgenic mice were immunized with Aβ1–42, which essentially prevented amyloid deposition; astrocytosis was dramatically reduced and there was reduction in Aβ‐induced inflammatory response as well. Aβ1–42 immunization also appeared to arrest the progression of amyloidosis in older PDAPP mice. Aβ immunization appears to increase clearance of amyloid plaques, and may therefore be a novel and effective approach for the treatment of AD.
Metal Chelation as a Potential Therapy for Alzheimer's Disease
Authors: CUAJUNGCO MATH P. , FAGÉT KYLE Y. , HUANG XUDONG , TANZI RUDOLPH E. , BUSH ASHLEY I.
Published: July 2010

Abstract: Alzheimer's disease is a rapidly worsening public health problem. The current lack of effective treatments for Alzheimer's disease makes it imperative to find new pharmacotherapies. At present, the treatment of symptoms includes use of acetyleholinesterase inhibitors, which enhance acetylcholine levels and improve cognitive functioning. Current reports provide evidence that the pathogenesis of Alzheimer's disease is linked to the characteristic neocortical amyloid‐β deposition, which may be mediated by abnormal metal interaction with Aβ as well as metal‐mediated oxidative stress. In light of these observations, we have considered the development of drugs that target abnormal metal accumulation and its adverse consequences, as well as prevention or reversal of amyloid‐β plaque formation. This paper reviews recent observations on the possible etiologic role of Aβ deposition, its redox activity, and its interaction with transition metals that are enriched in the neocortex. We discuss the effects of metal chelators on these processes, list existing drugs with chelating properties, and explore the promise of this approach as a basis for medicinal chemistry in the development of novel Alzheimer's disease therapeutics.
Cytidine (5′) Diphosphocholine Modulates Dopamine K+‐evoked Release in Striatum Measured by Microdialysis
Authors: AGUT J. , ORTIZ J. A. , WURTMAN R. J.
Published: July 2010

Abstract: Experiments were performed to determine whether exogenous cytidine (5′) diphosphocholine (CDP‐choline) could modify the release of dopamine (DA) in the striatum. Rats were divided into two groups, receiving either a standard diet (UAR 004) or the same diet supplemented with CDP‐choline (250 mg/kg day) for 28 days. On the last day the dialysis probes were inserted in the striatum, and DA, homovanillic acid (HVA), and 3,4‐dihydroxyphenylacetic acid (DOPAC) efflux were measured in the dialysis stream basally and during K+depolarization (80 mM K+). Basal DA, HVA, and DOPAC did not show any difference between treated and untreated groups. Depolarization with K+ increased DA levels by up to 3,000% in the control group and by up to 4,770% in the CDP‐choline‐treated group (p<0.05), and reduced extracellular HVA and DOPAC concentration by up to 45 and 35%, respectively, both in the untreated and CDP‐choline‐treated groups. These results show that long‐term treatment with CDP‐choline increases the K+ induced release of DA and suggest, in accordance with previous research, that by providing exogenous choline and cytidine, CDP‐choline modulates dopaminergic transmission.
VPAC1Receptors and Lung Cancer
Authors: MOODY T. W. , WALTERS J. , CASIBANG M. , ZIA F. , GOZES Y.
Published: July 2010

Abstract:VIP/PACAP are autocrine growth factors for lung cancer. VIP and/or PACAP mRNA is present in most lung cancer cell lines examined. Although mRNA for VPAC2‐R is not common, VPAC1‐R and PAC1‐R mRNA is present in many lung cancer cell lines.125I‐VIP binds with high affinity to lung cancer cells and specific125I‐VIP binding is inhibited with high affinity by (Lys15, Arg16, Leu27)VIP1–7GRF8–27, the VPAC1‐R specific agonist, but not by Ro25–155318, the VPAC2‐R specific agonist. VIP elevates cAMP and increases c‐fos gene expression. The increase in cAMP and c‐fos mRNA caused by VIP is inhibited by SN(VH). (SH)VH inhibited the proliferation of NCI‐H1299 cells in the MTT assay, which is based on cytotoxicity. In a recent cell line screen, (SN)VH inhibited the growth of 51 of 56 cancer cell lines including leukemia, lung cancer, colon cancer, CNS cancer, melanoma, ovarian cancer, renal cancer, breast cancer, and prostate cancer (T. Moody, unpublished). It remains to be determined if (SN)VH will be useful for treatment of a wide variety of cancers.
Downregulation of VPAC1R Expression in Breast Cancer Cell Lines
Authors: MADSEN BENTE , GEORG BIRGITTE , MADSEN MOGENS W. , FAHRENKRUG JAN
Published: July 2010

Abstract: The breast carcinoma cell line T47D was tested for 17β‐estradiol (E2) mediated regulation of vasoactive intestinal polypeptide receptor type‐1 (VPAC1) expression. E2 was found to downregulate the mRNA level. The number of VIP binding sites was reduced 66% on treatment with E2 for 72 h. Experiments with cycloheximide suggested that the effect was independent (at least partly so) of protein synthesis. Experiments with the transcriptional inhibitor, actinomycin D, showed that E2 did not influence the VPAC1 mRNA halflife. Both of two antiestrogens, ICI 182,780 and 4‐hydroxytamoxifen, mediated a concentration dependent inhibition of the effect of E2 on the mRNA level. Transient transfection with reporter‐gene constructs containing various portions of the VPAC1 5′‐flanking sequence revealed the most proximal 100 bp to be essential for the basal transcriptional activity. However, E2 did not influence the expression of the reporter gene using up to 3,250 bp of the VPAC1 5′‐flanking region.
Vasoactive Intestinal Peptide (VIP) Receptor Type 2 (VPAC2) is the Predominant Receptor Expressed in Human Thymocytes
Authors: LARA‐MARQUEZ MARIA L. , O'DORISIO M. SUE , KARACAY BAHRI
Published: July 2010

Abstract: Vasoactive intestinal peptide (VIP) binding sites have been identified in the human thymus, but the receptor subtype and how these receptors are distributed in the human thymus subsets is unknown. To assess gene expression, distribution, and receptor regulation of the two G‐protein‐associated VIP receptors, VPAC1 and VPAC2 mRNAs were quantified using a novel fluorometric‐based kinetic (real‐time) RT‐PCR. Bulk and fractionated thymocytes were stimulated via the TCR/CD3 receptor complex and anti‐CD28. Our results demonstrate that thymocytes express higher levels of VPAC2 compared to VPAC1 expression in bulk thymocytes, CD4+CD8+ selected double positives (DP), and CD8 depleted thymocytes. Double negative cells express low levels of VPAC2 mRNA. We demonstrate T‐cell activation‐dependent downregulation of VPAC1, but not VPAC2, in human thymocytes. This study reports the first direct evidence of a differential distribution and selective regulation of VPAC1 and VPAC2 gene expression in normal human thymocyte subsets.
VIP and PACAP Inhibit Activation Induced Apoptosis in T Lymphocytes
Authors: DELGADO MARIO , GANEA DOINA
Published: July 2010

Abstract:Apoptosis in T and B lymphocytes is a major element controlling the immune response. Activation induced cell death (AICD) in T cells is a main mechanism for maintaining peripheral tolerance and for limiting an ongoing immune response. AICD is initiated by antigen reengagement of the T cell receptor (TCR), and mediated through Fas/Fas ligand (FasL) interactions. VIP and PACAP are two multifunctional neuropeptides present in the lymphoid microenvironment that act primarily as anti‐inflammatory agents. In this study we report on the role of VIP and PACAP on T cell AICD, and on the mechanisms involved. VIP and PACAP inhibit AICDin vivoandin vitro, in peripheral T cells and T cell hybridomas. The effect is dose dependent and is mediated through the specific receptors VPAC1and VPAC2. The inhibition of AICD is achieved through reduction in FasL expression at protein and mRNA level. By affecting FasL expression, VIP and PACAP may play a physiological role in both the generation of memory T cells and the inhibition of FasL‐mediated T cell cytotoxicity.
Neuroprotective Effects of PACAP38 in a Rat Model of Transient Focal Ischemia under Various Experimental Conditions
Authors: REGLODI DORA , SOMOGYVARI‐VIGH ANIKO , VIGH SANDOR , MADERDRUT JEROME L. , ARIMURA AKIRA
Published: July 2010

Abstract: In the study reported here, we investigated the neuroprotective effect of PACAP38 in a rat model of middle cerebral artery occlusion (MCAO) under various experimental conditions. Stroke patients often develop mild hyperthermia that increases the infarct size and worsens the outcome. We compared the neuroprotective effect of PACAP38 in normothermic and moderately hyperthermic animals. Brain damage was more extensive in the hyperthermic animals, but PACAP38 significantly reduced the infarct size, measured 48 h after MCAO, in both the normothermic and the moderately hyperthermic animals, by more than 50%. However, a significant neuroprotection with PACAP38 could only be demonstrated when animals with no definite circling behavior and/or convulsions were excluded from the evaluations. In conclusion, moderate hyperthermia did not influence the effect of PACAP38, but animals with questionable brain damage or convulsions must be excluded from the sample in order to demonstrate the neuroprotection with PACAP38.
Characterization of Intestinal Receptors for VIP and PACAP in Rat and in PAC1Receptor Knockout Mouse
Authors: EKBLAD E. , JONGSMA H. , BRABET P. , BOCKAERT J. , SUNDLER F.
Published: July 2010

Abstract:The receptors for VIP and PACAP were characterizedin vitroon rat ileal and colonic longitudinal smooth muscle with adherent myenteric ganglia. Colon strips from PAC1 receptor knockout and wildtype mice were also examined. VIP, PACAP‐38 and PACAP‐27 all caused concentration dependent relaxations. In rat ileum three different types of smooth muscle VIP/PACAP receptors were defined: (1) a PACAP‐27 preferring receptor coupled to apamin sensitive Ca2+‐dependent K+channels, (2) a PAC1receptor activated by both PACAP‐27 and PACAP‐38, and (3) a VIP specific receptor regulated by NPY. The receptors identified in rat colon were: (1) a PAC1receptor localized on NO synthesizing neurones. Activation leads to increased NO production. (2) A smooth muscle PAC1receptor. The responses elicited by both receptors were abolished by apamin. (3) A smooth muscle VIP specific receptor. PAC1receptor knockout mice did not respond to PACAP‐27 or PACAP‐38, whereas VIP induced a relaxatory response indicating the presence of a VIP specific receptor. In wildtype mice all three peptides elicited relaxatory responses. Pharmacological characterization of intestinal VIP/PACAP receptors indicates the existence of receptors, such as a PACAP‐27 preferring receptor and a VIP specific receptor, distinct from those that have been cloned (VPAC1, VPAC2, and PAC1).
Mutational Analysis of the Glucose Regulatory Element in the Promoter of the Glucagon Receptor Gene
Authors: PORTOIS LAURENCE , TASTENOY MICHÈLE , SVOBODA MICHAL
Published: July 2010

Abstract: Recently, we identified a glucose regulatory element in the promoter of the rat glucagon receptor gene. The effect of glucose is centered on a highly palindromic sequence of 19 nucleotides that we called the G box (Portois et al., 1999, J. Biol. Chem. 274: 8181–8190). This sequence contains two E boxes. Recently, we investigated the role of each individual E box, as well as the contribution of the sequences located upstream and downstream from this G box. (1) Mutation of nucleotides “CA” to “GT” in the first E box (position ‐543 to ‐542) suppressed the activation of the CAT reporter gene by glucose. In contrast, mutation of the nucleotides “CA” to “GT” in the second E box (position ‐534 to ‐533) had no effect on this glucose activation. (2) Deletion of a sequence upstream from the G box (nucleotides ‐579 to ‐555) suppressed the activation by glucose, whereas deletion of a sequence located downstream from the G box (nucleotides ‐501 to ‐443) had no effect on this parameter. (3) Subcloning of a small promoter fragment of only 49 nucleotides (‐560 to ‐512) into the pCat5 plasmid conferred to transfected cells sensitivity to glucose in terms of CAT activity. Consequently, all transactivation factors required for this glucose effect must act via this short gene fragment.
Regulation of Vasoactive Intestinal Peptide Receptor Expression in Developing Nervous Systems
Authors: KARACAY BAHRI , O'DORISIO M SUE , SUMMERS MONICA , BRUCE JARROD
Published: July 2010

Abstract: Vasoactive intestinal peptide (VIP) is a 28‐amino acid neuropeptide that has several functions, including the regulation of water and electrolyte secretion, hormone and cytokine release, bronchodilitation, and neurogenesis. VIP effects are mediated by specific G‐protein coupled receptors. Three distinct receptor subtypes, with differing affinity for VIP, have been cloned and characterized as receptors 1 and 2 (VPAC1 and VPAC2) and pituitary adenylate cyclase activating polypeptide receptor (PAC1). Our laboratory has demonstrated that upregulation of VPAC1 in SK‐N‐SH neuroblastoma cells results in marked shift in cell type to the glial lineage with a corresponding loss of neuronal lineage and suppression of xenograft tumor growth.1 To understand the molecular mechanisms responsible for regulation of the VPAC1 gene in neuronal lineage, we have cloned and sequenced 2.6‐kb of the 5′‐flanking sequences of the human VPAC1 gene. Sequence analysis demonstrated that the human VPAC1 promoter sequence contains putative binding sites for several known transcription factors, including Sp1, NFkB, and cETS‐1. To study the temporal and spatial expression pattern of human VPAC1 promoter sequences, we have generated transgenic mice expressing the bacterial β‐galactosidase gene under the control of the 2.6‐kb 5′‐flanking and promoter sequence of the human VPAC1 gene. Transgene expression was detected in brain, spinal cord, and lung in 14‐day‐old animals. Taken together, these results demonstrate that VPAC1 may play an important role in the nervous system, and suggest a role for VIP in neuronal differentiation.
Molecular and Biological Determinants of the Cytotoxic Actions of Camptothecins: Perspective for the Development of New Topoisomerase I Inhibitors
Authors: KOHN KURT W. , POMMIER YVES
Published: July 2010

Abstract: Camptothecin, originally discovered in 1957 as an antitumor activity in plant extracts, has recently become one of the most promising leads to new anticancer drugs. After lingering for many years, interest in camptothecin was revitalized in 1985 upon discovery of its specific action on topoisomerase I. Detailed elucidation of action mechanisms at the molecular, cellular, and pharmacologic levels has made camptothecin and its congeners perhaps the best understood among clinical anticancer drugs. Promising chemical variants of camptothecin, and recently other chemical categories of topoisomerase I‐targeted drugs, provide unusually rich opportunities for rational drug selection and design. This is made possible by current concepts based, for the most part, on a sound experimental foundation, which points the way towards optimally effective therapy.
Mechanisms of Resistance to Camptothecins
Authors: SALEEM AHAMED , EDWARDS TROY K. , RASHEED ZESHAAN , RUBIN ERIC H.
Published: July 2010

Abstract:Camptothecins are broad‐spectrum anticancer drugs that specifically target DNA topoisomerase I. Although the availability of camptothecins has had a significant impact on cancer therapeutics, de novo or acquired clinical resistance to camptothecins is common. Studies of camptothecin resistance using yeast and mammalian cell culture models suggest three general mechanisms of resistance: (1) reduced cellular accumulation of camptothecins, (2) alteration in the structure or location of topoisomerase I, and (3) alterations in the cellular response to camptothecin‐DNA‐ternary complex formation. The relevance of these mechanisms to clinical drug resistance is not yet known, but evaluation of these models in clinical specimens should enhance the use of camptothecins both as single agents and in combination with other anticancer drugs.
Structure‐Based Analysis of the Effects of Camptothecin on the Activities of Human Topoisomerase I
Authors: CHAMPOUX JAMES J.
Published: July 2010

Abstract:The sole target for the anticancer drug camptothecin (CPT) is the type I topoisomerase. The drug poisons the topoisomerase by slowing the religation step of the reaction, thereby trapping the enzyme in a covalent complex on the DNA. In addition, CPT has been shown to inhibit plasmid DNA relaxationin vitro. The structural bases for these two activities of CPT are explored in relation to the recently published crystal structure of the enzyme with bound DNA.
Homocamptothecins: E‐Ring Modified CPT Analogues
Authors: LAVERGNE OLIVIER , DEMARQUAY DANIELE , KASPRZYK PHILIP G. , BIGG DENNIS C.H.
Published: July 2010

Abstract: Homocamptothecins (hCPT) are modified camptothecins (CPT) with a seven‐membered β‐hydroxylactone instead of the naturally occurring six‐membered α‐hydroxylactone. This E‐ring modification fully conserves the ability to stabilize topo I‐DNA single‐strand breaks and stimulates high levels of DNA cleavage. A key feature is the irreversibility of E‐ring opening, which should give reduced toxicity. Substituted hCPTs have been selected for their high antiproliferative activity on a panel of tumor cell lines, including those with cross resistance, and were found to be active at very low doses in a variety of human tumor xenografts when administered orally. BN 80915, a difluoro‐hCPT, has entered clinical trials.
Structure‐Activity Relationship of Alkyl Camptothecin Esters
Authors: CAO ZHISONG , FANTAZIS PANAYOTIS , MENDOZA JOHN , EARLY JANET , KOZIELSKI ANTHONY , HARRIS NICK , VARDEMAN DANA , LIEHR JOACHIM , STEHLIN JOHN S. , GIOVANELLA BEPPINO
Published: July 2010

Abstract:The cytotoxicity of camptothecin (CPT) esters 1–6 was measured. Like parental camptothecin, esters 2 and 3, but not 1, 4, 5, and 6, inhibited proliferation of human leukemia cells in culture and induced programmed cell death as assessed by flow cytometry studies. Exhibition of similar levels of antiproliferative activities of CPT 2 and 3 required different incubation time periods in cell cultures, with CPT and 3 requiring the shortest and longest periods, respectively. Both 2 and 3 were inactive against cells resistant to the semisynthetic CPT derivative 9‐nitrocamptothecin and unable to stabilize DNA‐topoisomerase I (Topo I) “cleavable complexes” in a cell‐free system, suggesting that Topo I activity was required but insufficient for the mechanism of action of 2 and 3. Mouse liver homogenate converted esters to parental CPT, but the conversion rates were different with different esters. Of four tested esters in this experiment, ester 2 had the fastest conversion rate.In vivostudies showed that ester 2 had an exceptional lack of toxicity in nude mice, even at enormous doses, and demonstrated extensive activity against human breast and colon tumors grown as xenografts in immunodeficient nude mice, whereas no antitumor activity was observed for the other esters. In conclusion, ester 2 is a prodrug of the antitumor compound CPT, and it can be administered at very high doses in mice with no appearance of toxicity. This study provides a basis for further evaluation of CPT ester 2 as an investigational anticancer agent.
Intraperitoneal Topoisomerase‐I Inhibitors: Preliminary Findings with 9‐Aminocamptothecin
Authors: MUGGIA FRANCO , LIEBES LEONARD , POTMESIL MILAN , HAMILTON ANNE , HOCHSTER HOWARD , HORNREICH GILA , SORICH JOAN , DOWNEY ANDREA , WASSERSTROM HEATHER
Published: July 2010

Abstract: The i.p. administration of topoisomerase I (Topo I) inhibitors has a pharmacologic advantage over intravenous application, including preservation of the biologically active lactone form. In our ongoing study, patients have received 9‐amino‐20(S)‐camptothecin (9‐AC) i.p. on days 1, 3, 5, 8, 10, and 12, repeated every 4 weeks. The daily dose has been escalated to level IV of 1.5 mg/m2 (9.0 mg/m2 per course), median of 3 cycles, range 1–4, with a reversible Grade 3 neutropenia in one patient. Responses included one CR (resolution of a pleural effusion), two patients without progressive disease (PD), two not evaluable, and two patients too early for evaluation. The area under the curve (AUC)ip/AUCpl ratio (pharmacologic advantage) ranged from 7.6 to 16.5 on average, and, using nonlinear modeling, the pharmacologic decay data were fit to one‐ or two‐compartmental models. Overall, a 9‐AC i.p. application is well tolerated and anticipated to be an active regimen against i.p. malignancies, particularly those known to be sensitive to systemic Topo‐I inhibitors.
Metabolism of CPT‐11: Impact on Activity
Authors: RIVORY LAURENT P.
Published: July 2010

Abstract:Irinotecan (CPT‐11) is a semi‐synthetic camptothecin with a broad spectrum of clinical activity. It is a prodrug that is cleaved by esterases to the potent topoisomerase I poison, SN‐38. In humans, this activation is relatively inefficient, but this may result in a more protracted formation of SN‐38 lactone. Some intratumoral activation may also occur, but the significance of this process is uncertain. CPT‐11 is metabolized by cytochrome P450 3A to yield a number of comparatively inactive compounds. SN‐38 is glucurono‐conjugated in the liver, and this metabolite, although inactive, may participate in the enterohepatic cycling of SN‐38 after hydrolysis in the intestinal lumen. Overall, the production of SN‐38 from CPT‐11 is the result of the complex interplay of several metabolic pathways and the source of considerable interpatient variability.
Pharmacology of Camptothecin Esters
Authors: LIEHR JOACHIM G. , HARRIS NICK J. , MENDOZA JOHN , AHMED AHMED E. , GIOVANELLA BEPPINO C.
Published: July 2010

Abstract: An intact lactone ring of camptothecins is a structural requirement for their anticancer activity. Propionate esters of camptothecin (CPT) and 9‐nitrocamptothecin (9NC), CZ48 and CZ112, respectively, have been synthesized as derivatives resistant to lactone hydrolysis and are chemotherapeutically active. In this study, we have examined the mechanism of action of CZ48 and CZ112 and their distribution, metabolism, and toxicity. CZ112 incubated in human plasma retained its lactone structure longer than 9NC (t1/2: 10.5 and <1 hr for CZ112 and 9NC, respectively). This resistance to lactone hydrolysis was also observed in mouse plasma or albumin solutions. Neither CZ48 nor CZ112 inhibit topoisomerase I and thus are prodrugs dependent on hydrolysis to CPT or 9NC, respectively. Rates of hydrolysis of CZ48 to CPT are higher by homogenates of mouse liver, spleen, lung, and kidney than by plasma. Rates of hydrolysis by tumor cells in culture vary and were higher by breast cancer and melanoma cells than by colon cancer cells. On the basis of these and other data, it is proposed that CZ48 and CZ112 may act as anticancer agents by resisting hydrolysis to camptothecins while in circulation. Hydrolysis in tissues may release intact lactone in target tissues.
Topotecan (Hycamptin) and Topotecan‐Containing Regimens in the Treatment of Hematologic Malignancies
Authors: BERAN MILOSLAV , KANTARJIAN HAGOP M.
Published: July 2010

Abstract: Single‐agent topotecan is an active drug in chemotherapy‐naive MDS and CMML and, to a lesser degree, in refractory/relapsed acute leukemias, low‐/intermediate‐grade lymphoma, and myeloma. Its combination with cytosine arabinoside induces complete remissions in high‐risk MDS/CMML. A triple‐combination regimen of cyclophosphamide, cytosine arabinoside, and topotecan (CAT) was extensively tested in refractory/relapsed as well as in untreated AML. By proving effective in inducing complete remission in newly diagnosed AML at rates comparable to those achieved by anthracycline‐cytosine arabinoside regimens, for example, CAT offers a useful treatment alternative. Topotecan combined with paclitaxel is promising in low‐/intermediate‐grade lymphomas. The activity of topotecan justifies further evaluation of topotecan‐containing combination regimens, particularly in MDS/CMML and acute leukemias.
Cellular and Molecular Responses to Topoisomerase I Poisons: Exploiting Synergy for Improved Radiotherapy
Authors: MIYAMOTO SHIGEKI , HUANG TONY T. , WUERZBERGER‐DAVIS SHELLY , BORNMANN WILLIAM G. , PINK JOHN J. , TAGLIARINO COLLEEN , KINSELLA TIMOTHY J. , BOOTHMAN DAVID A.
Published: July 2010

Abstract:The efficacy of topoisomerase (Topo) I‐active drugs may be improved by better understanding the molecular and cellular responses of tumor compared to normal cells after genotoxic insults. Ionizing radiation (IR) + Topo I‐active drugs (e.g., Topotecan) caused synergistic cell killing in various human cancer cells, even in cells from highly radioresistant tumors. Topo I poisons had to be added either during or immediately after IR. Synergy was caused by DNA lesion modification mechanisms as well as by concomitant stimulation of two pathways of cell death: necrosis (IR) + apoptosis (Topo I poisons). Cumulative data favor a mechanism of synergistic cell killing caused by altered DNA lesion modification and enhanced apoptosis. However, alterations in cell cycle regulation may also play a role in the synergy between these two agents in certain human cancers. We recently showed that NF‐κB, a known anti‐apoptotic factor, was activated in various cancer cells after poisoning Topo I using clinically active drugs. NF‐κB activation was dependent on initial nuclear DNA damage followed by cytoplasmic signaling events. Cytoplasmic signaling leading to NF‐κB activation after Topo I poisons was diminished in cytoplasts (lacking nuclei) and in CEM/C2 cells that expressed a mutant Topo I protein that did not interact with Topo I‐active drugs. NF‐κB activation was intensified in S‐phase and blocked by aphidicolin, suggesting that activation was a result of double‐strand break formation due to Topo I poisoning and DNA replication. Dominant‐negative IkB expression augmented Topo I poison‐ mediated apoptosis. Elucidation of molecular signal transduction pathways after Topo I drug‐IR combinations may lead to improved radiotherapy by blocking anti‐apoptotic NF‐κB responses. Recent data also indicate that synergy caused by IR + Topo I poisons is different from radiosensitization by β‐lapachone (β‐lap), a “reported” Topo I and II‐α poisonin vitro. In fact, β‐lap does not kill cells by poisoning either Topo I or II‐αin vivo. Instead, the compound is “activated” by an IR (damage)‐inducible enzyme, NAD(P)H:quinone oxidoreductase (NQO1), a gene cloned as x‐ray‐inducible transcript #3, xip3. Unlike the lesion modification pathway induced by IR + Topo I drugs, β‐lap kills cells via NQO1 futile cycle metabolism. Downstream apoptosis caused by β‐lap appears to be noncaspase‐mediated, involving calpain or a calpain‐like protease. Thus, although Topo I poisons or β‐lap in combination with IR both synergistically kill cancer cells, the mechanisms are very different.
Athens and/or Jerusalem
Authors: PELIKAN JAROSLAV
Published: July 2010

Abstract:For all three cosmic questions—“Did the universe have a beginning?”“Is the universe designed?” and “Are we alone?”—it was the conjunction as well as the divergence between Athens (Classical philosophy, especially Plato'sTimaeusand Aristotle'sPhysics) and Jerusalem (the Bible, especially the Book of Genesis and the apostle Paul) that illumined the questions themselves, provided material for the answers, and set the terms for the subsequent discussion of them in later centuries.
A Recipe for Primordial Soup
Authors: KOLB EDWARD (ROCKY)
Published: July 2010

Abstract: If the universe emerged from a state of high temperature and high density, we can study the origin of the universe by recreating those conditions in the laboratory. While we can not reproduce the Big Bang, we can recreate its conditions and study the physical processes responsible for producing the rich and varied universe we observe today.
Cosmic Design from a Buddhist Perspective
Authors: THUAN TRINH XUAN
Published: July 2010

Abstract: The Buddhist view of the origin of the universe is discussed. One of the basic tenets of Buddhism is the concept of interdependence which says that all things exist only in relationship to others, and that nothing can have an independent and autonomous existence. The world is a vast flow of events that are linked together and participate in one another. Thus there can be no First Cause, and no creation ex nihilo of the universe, as in the Big Bang theory. Since the universe has neither beginning nor end, the only universe compatible with Buddhism is a cyclic one. According to Buddhism, the exquisitely precise fine‐tuning of the universe for the emergence of life and consciousness as expressed in the “anthropic principle” is not due to a Creative Principle, but to the interdependence of matter with flows of consciousness, the two having co‐existed for all times.
Are We Alone?
Authors: VIA SARA
Published: July 2010

Abstract: The understanding of life on Earth that we have obtained from the science of evolutionary biology offers clues to the qustion of what life might be like if found elsewhere. After presenting the basics of the evolutionary process, I discuss the factors that determine the outcome of evolution, the role of key innovations and extinction in evolution, and whether the evolution of human life is inevitable.
Homes for Extraterrestrial Life
Authors: LATHAM DAVID W.
Published: July 2010

Abstract: Astronomers are now discovering giant planets orbiting other stars like the sun by the dozens. But none of these appears to be a small rocky planet like the earth, and thus these planets are unlikely to be capable of supporting life as we know it. The recent discovery of a system of three planets is especially significant because it supports the speculation that planetary systems, as opposed to single orbiting planets, may be common. Our ability to detect extrasolar planets will continue to improve, and space missions now in development should be able to detect earth‐like planets.
What is SETI?a
Authors: TARTER JILL
Published: July 2010

Abstract: This paper describes the efforts of SETI that are going on around the world. It presents a brief rationale for the choice of methodology and the limits that can be set on the basis of such results to date.
Vector Surveillance for West Nile Virus
Authors: WHITE DENNIS J.
Published: July 2010

Abstract: West Nile virus (WNV) was detected in the metropolitan New York City (NYC) area during the summer and fall of 1999. Sixty‐two human cases, including seven fatalities, were documented. The New York State Department of Health (NYSDOH) initiated and implemented a statewide mosquito and WNV surveillance system. We developed a WNV response plan designed to provide local health departments (LHD) a standardized means to begin to assess basic mosquito population data and to detect WNV circulation in mosquito populations. During the 2000 arbovirus surveillance season, local health agencies collected 317,676 mosquitoes and submitted 9,952 pools for virus testing. NYSDOH polymerase chain reaction (PCR) testing detected 363 WNV‐positive pools. Eight species of mosquitoes were found to be infected. Of the 26 counties conducting mosquito surveillance, WNV‐positive mosquitoes were detected only in NYC, on Long Island, and in four counties in the lower Hudson River valley region. LHD larval surveillance provided initial or enhanced mosquito habitat location and characterization and mosquito species documentation. Adult mosquito surveillance provided LHD information on species' presence, density, seasonal fluctuations, virus infection, minimum infection ratios (MIR) and indirect data on mosquito control efficacy after larval or adult control interventions. Collective surveillance activities conducted during 1999 and 2000 suggest that WNV has dispersed throughout the state and may affect local health jurisdictions within NYS, adjacent states, and Canada in future years. Vector surveillance will remain a critical component of LHD programs addressing public health concerns related to WNV.
Epidemic West Nile Encephalitis in Romania
Authors: CAMPBELL GRANT L. , CEIANU CORNELIA S. , SAVAGE HARRY M.
Published: July 2010

Abstract: Seroprevalence data suggest that West Nile virus activity in southern Romania dates to the 1960s or earlier. In the summer of 1996, southeastern Romania and especially Bucharest experienced an unprecedented epidemic of West Nile encephalitis/meningitis, with at least 393 hospitalized cases and 17 deaths. Contributing factors included a susceptible avian population and urban/suburban infrastructural conditions that favored the production of large numbers of Culex pipiens pipiens. The epidemic ended spontaneously in early autumn. Results of serosurveys conducted as the epidemic waned pointed to the recent, novel introduction of West Nile virus to Bucharest. During 1997‐2000, 39 scattered human cases of clinical West Nile virus infection (mean, 10 per year; range, 5‐14 per year)—including 5 (13%) fatal cases—were diagnosed serologically throughout the region, but epidemic disease did not recur. Results of limited ecologic surveillance efforts during 1997‐2000 suggested the existence of numerous focal areas of enzootic West Nile virus activity within the region. The authors explore the possible factors that led to the 1996 epidemic, review the ecologic and human data gathered during the postepidemic period of 1997‐2000, summarize the public health lessons offered by the epidemic and its aftermath, and speculate on the future of epidemic West Nile virus activity in southeastern Romania.
West Nile in the Mediterranean Basin: 1950‐2000
Authors: MURGUE B. , MURRI S. , TRIKI H. , DEUBEL V. , ZELLER H. G.
Published: July 2010

Abstract: Recent West Nile virus (WNV) outbreaks have occurred in the Mediterranean basin. In Algeria in 1994, about 50 human cases of WN encephalitis were suspected, including 8 fatal cases. In Morocco in 1996, 94 equines were affected of which 42 died. In Tunisia in 1997, 173 patients were hospitalized for encephalitis or meningoencephalitis. West Nile serology performed on 129 patients was positive in 111 cases (87%) including 5 fatal cases. In Italy in 1998, 14 horses located in Tuscany were laboratory confirmed for WNV infection; 6 animals died. In Israel in 1998, serum samples from horses suffering from encephalomyelitis had WNV antibodies and virus was isolated from the brain of a stork; in 1999 WNV was identified in commercial geese flocks, and in 2000 hundreds of human cases have been reported. In September 2000, WNV infection was detected in horses located in southern France, close to the Camargue National Park where a WNV outbreak occurred in 1962. By November 30, 76 cases were laboratory confirmed among 131 equines presenting with neurological disorders. No human case has been laboratory confirmed among clinically suspect patients. The virus isolated from a brain biopsy is closely related to the Morocco‐1996 and Italy‐1998 isolates from horses, to the Senegal‐1993 and Kenya‐1998 isolates from mosquitoes, and to the human isolate from Volgograd‐1999. It is distinguishable from the group including the Israel‐1998 and New York‐1999 isolates, as well as the Tunisia‐1997 human isolate.
Kunjin Virus
Authors: HALL ROY A. , SCHERRET JACQUELINE H. , MACKENZIE JOHN S.
Published: July 2010

Abstract: Kunjin (KUN) is a flavivirus in the Japanese encephalitis antigenic complex that was first isolated from Culex annulirostris mosquitoes captured in northern Australia in 1960. It is the etiological agent of a human disease characterized by febrile illness with rash or mild encephalitis and, occasionally, of a neurological disease in horses. KUN virus shares a similar epidemiology and ecology with the closely related Murray Valley encephalitis (MVE) virus, the major causative agent of arboviral encephalitis in Australia. Based on traditional antigenic methods, KUN was initially found to be similar to, but distinct from, reference strains of West Nile (WN) virus and designated as a new species. However, more recent phylogenic analyses have revealed that some strains of WN virus, including the isolates from New York, are more similar to KUN virus and form a separate lineage to other WN viruses. An unusual KUN isolate from Malaysia and the African virus Koutango appear to form additional lineages within the WN group of viruses. While these findings are in agreement with the Seventh Report of the International Committee for the Taxonomy of Viruses that designates KUN as a subtype of West Nile, they also suggest that the species should be further subdivided into additional subtypes.
West Nile Encephalitis
Authors: SAMPSON BARBARA A. , ARMBRUSTMACHER VERNON
Published: July 2010

Abstract: West Nile virus was identified by immunohistochemistry (IHC) and polymerase chain reaction (PCR) as the etiologic agent in four encephalitis fatalities in New York City in the late summer of 1999. Fever and profound muscle weakness were the predominant symptoms. Autopsy disclosed encephalitis in two instances and meningoencephalitis in the remaining two. The inflammation was mostly mononuclear and formed microglial nodules and perivascular clusters in the white and gray matter. The brain stem, particularly the medulla, was involved most extensively. In two brains, cranial nerve roots had endoneural mononuclear inflammtion. In addition, one person had acute pancreatitis. On the basis of our experience, we offer recommendations for the autopsy evaluation of suspected WNV fatalities.
Use of Live and Inactivated Vaccines in the Control of West Nile Fever in Domestic Geese
Authors: MALKINSON M. , BANET C. , KHINICH Y. , SAMINA I. , POKAMUNSKI S. , WEISMAN Y.
Published: July 2010

Abstract: The recent epizootic of West Nile fever in Israel affected predominantly young domestic geese between three and eight weeks old. Clinically, the birds presented paralytic signs while morbidity and mortality were severe in affected flocks. The condition was encountered from early September through late November on goose farms located throughout the country. Losses incurred by goose flocks were sufficiently great as to warrant investigation of ways to protect young geese against the neurological form of the disease. We have conducted a series of vaccination trials in which three‐week old geese were immunized with an attenuated, commercial flavivirus vaccine derived from Israel turkey meningoencephalitis virus (TME). Birds were challenged two weeks later with a low Vero cell passage of West Nile virus by the intracerebral route. In a second group of experiments, inactivated and live TME vaccines were given in tandem at an interval of two weeks and challenged two weeks later. The third vaccination trial was based on West Nile virus (WNV) harvested from infant mouse brain, inactivated with formalin and oil adjuvanted. A single injection given either subcutaneously or intramuscularly resulted in 75% protection of the vaccinated groups, while two injections spaced two weeks apart resulted in 94% protection. Groups of geese, vaccinated at the farms and challenged under controlled conditions in the laboratory, showed levels of protection ranging from 39% to 72% for TME vaccine and 52% and 80% for WNV vaccine. The lower levels of protection are attributable to flocks being affected with intercurrent infections at the time of vaccination.
Antibody Prophylaxis and Therapy for Flavivirus Encephalitis Infections
Authors: ROEHRIG JOHN T. , STAUDINGER LISA A. , HUNT ANN R. , MATHEWS JAMES H. , BLAIR CAROL D.
Published: July 2010

Abstract: The outbreak of West Nile (WN) encephalitis in the United States has rekindled interest in developing direct methods for prevention and control of human flaviviral infections. Although equine WN vaccines are currently being developed, a WN vaccine for humans is years away. There is also no specific therapeutic agent for flaviviral infections. The incidence of human WN virus infection is very low, which makes it difficult to target the human populations in need of vaccination and to assess the vaccine's economic feasibility. It has been shown, however, that prophylactic application of antiflaviviral antibody can protect mice from subsequent virus challenge. This model of antibody prophylaxis using murine monoclonal antibodies (MAbs) has been used to determine the timing of antibody application and specificity of applied antibody necessary for successful prophylaxis. The major flaviviral antigen is the envelope (E) glycoprotein that binds cellular receptors, mediates cell membrane fusion, and contains an array of epitopes that elicit virus‐neutralizing and nonneutralizing antibodies. The protective efficacy of an E‐glycoprotein‐specific MAb is directly related to its ability to neutralize virus infectivity. The window for successful application of prophylactic antibody to prevent flaviviral encephalitis closes at about 4 to 6 days postinfection concomitant with viral invasion of the brain. Using murine MAbs to modify human disease results in a human antimouse antibody (HAMA) response that eventually limits the effectiveness of subsequent murine antibody applications. To reduce the HAMA response and make these MAbs more generally useful for humans, murine MAbs can be “humanized” or human MAbs with analogous reactivities can be developed. Antiflaviviral human or humanized MAbs might be practical and cost‐effective reagents for preventing or modifying flaviviral diseases.
Potential North American Vectors of West Nile Virus
Authors: TURELL MICHAEL J. , SARDELIS MICHAEL R. , DOHM DAVID J. , O'GUINN MONICA L.
Published: July 2010

Abstract: The outbreak of disease in the New York area in 1999 due to West Nile (WN) virus was the first evidence of the occurrence of this virus in the Americas. To determine potential vectors, more than 15 mosquito species (including Culex pipiens, Cx. nigripalpus, Cx. quinquefasciatus, Cx. salinarius, Aedes albopictus, Ae. vexans, Ochlerotatus japonicus, Oc. sollicitans, Oc. taeniorhynchus, and Oc. triseriatus) from the eastern United States were evaluated for their ability to serve as vectors for the virus isolated from birds collected during the 1999 outbreak in New York. Mosquitoes were allowed to feed on one‐ to four‐day old chickens that had been inoculated with WN virus 1‐3 days previously. The mosquitoes were incubated for 12‐15 days at 26°C and then allowed to refeed on susceptible chickens and assayed to determine transmission and infection rates. Several container‐breeding species (e.g., Ae. albopictus, Oc. atropalpus, and Oc. japonicus) were highly efficient laboratory vectors of WN virus. The Culex species were intermediate in their susceptibility. However, if a disseminated infection developed, all species were able to transmit WN virus by bite. Factors such as population density, feeding preference, longevity, and season of activity also need to be considered in determining the role these species could play in the transmission of WN virus.
Development of Bowman‐Birk Inhibitor for Chemoprevention of Oral Head and Neck Cancer
Authors: MEYSKENS FRANK L.
Published: July 2010

Leukoplakia in the oral cavity has been used as a putative surrogate marker of head and neck cancer development. A class of chemoprevention compounds, called protease inhibitors, has been shown in vitro and in animal models to effectively suppress premalignant lesions. Bowman‐Birk inhibitor (BBI) is a protease inhibitor derived from soybeans that has demonstrated chemoprevention activity in many in vitro and animal systems, including the hamster cheek pouch model. Pilot, Phase I and Phase IIa studies of Bowman‐Birk Inhibitor in patients with oral leukoplakia have demonstrated no detectable side effects. In the Phase IIa trial, changes in the protease activity in oral mucosal cells after BBI Concentrate© (BBIC) treatment correlated with the changes in neu protein levels. Additionally, evidence for a dose‐related treatment effect of BBIC on oral leukoplakia was demonstrated. These results indicate that BBIC should be investigated for chemopreventive activity in a randomized clinical trial.