bluuebunny/crossref_metadata_2025 huggingface dataset:
The Tumor Antigen Repertoire Identified in Tumor-Bearing Neu Transgenic Mice Predicts Human Tumor Antigens
Authors: Lu Hailing , Knutson Keith L. , Gad Ekram , Disis Mary L.
Published: October 2006

FVB/N mice transgenic for nontransforming rat neu develop spontaneous breast cancers that are neu positive and estrogen receptor negative, mimicking premenopausal human breast cancer. These animals have been widely used as a model for immunobased therapies targeting HER-2/neu. In this study, we used serological analysis of recombinant cDNA expression libraries to characterize the antigenic repertoire of neu transgenic (neu-tg) mice and questioned the ability of this murine model to predict potential human tumor antigens. After screening 3 × 106 clones from 3 different cDNA libraries, 15 tumor antigens were identified, including cytokeratin 2-8, glutamyl-prolyl-tRNA synthetase, complement C3, galectin 8, and serine/threonine-rich protein kinase 1. Multiple proteins involved in the Rho/Rho-associated, coiled coil–containing protein kinase (Rock) signal transduction pathway were found to be immunogenic, including Rock1, Rho/Rac guanine nucleotide exchange factor 2, and schistosoma mansoni adult worm antigen preparation 70. All of the identified antigens are self-proteins that are expressed in normal tissues in addition to breast tumors and the majority of the antigens are intracellular proteins. More than half of the mouse tumor antigens have human homologues that have been reported previously as tumor antigens. Finally, the tumor-specific antibody immunity and marked immune cell infiltration that was observed in mice with spontaneous tumors were not observed in mice with transplanted tumors. Our results indicate that neu-tg mice bearing spontaneous tumors develop humoral immunity to their tumors similar to cancer patients and that tumor antigens identified in transgenic mouse may predict immunogenic human homologues. (Cancer Res 2006; 66(19): 9754-61)
Genetic Interaction between Rb and N-ras: Differentiation Control and Metastasis
Authors: Takahashi Chiaki , Ewen Mark E.
Published: October 2006

The retinoblastoma tumor suppressor gene, Rb, and the ras proto-oncogenes regulate various cellular processes, including differentiation and proliferation. Rb and ras genetically interact to positively influence differentiation in the mouse. This genetic interaction between Rb and ras also affects tumor development, either positively or negatively depending on cell type. Loss of one or two N-ras alleles allows medullary thyroid (C cell) adenomas occurring in Rb heterozygous mice to progress to metastatic carcinomas, an event associated with C cells displaying a less-differentiated phenotype. Here, we discuss the genetic interaction between Rb and ras and the development of a mouse model of medullary thyroid carcinoma. (Cancer Res 2006; 66(19): 9345-8)
Identification of a Chemical Inhibitor of the Oncogenic Transcription Factor Forkhead Box M1
Authors: Radhakrishnan Senthil K. , Bhat Uppoor G. , Hughes Douglas E. , Wang I-Ching , Costa Robert H. , Gartel Andrei L.
Published: October 2006

The oncogenic transcription factor forkhead box M1 (FoxM1) is overexpressed in a number of different carcinomas, whereas its expression is turned off in terminally differentiated cells. For this reason, FoxM1 is an attractive target for therapeutic intervention in cancer treatment. As a first step toward realizing this goal, in this study, using a high-throughput, cell-based assay system, we screened for and isolated the antibiotic thiazole compound Siomycin A as an inhibitor of FoxM1. Interestingly, we observed that Siomycin A was able to down-regulate the transcriptional activity as well as the protein and mRNA abundance of FoxM1. Consequently, we found that the downstream target genes of FoxM1, such as Cdc25B, Survivin, and CENPB, were repressed. Also, we observed that consistent with earlier reports of FoxM1 inhibition, Siomycin A was able to reduce anchorage-independent growth of cells in soft agar. Furthermore, we found that Siomycin A was able to induce apoptosis selectively in transformed but not normal cells of the same origin. Taken together, our data suggest that FoxM1 inhibitor Siomycin A could represent a useful starting point for the development of anticancer therapeutics. (Cancer Res 2006; 66(19): 9731-5)
Autophagy in Cancer: Good, Bad, or Both?
Authors: Hippert Melanie M. , O'Toole Patrick S. , Thorburn Andrew
Published: October 2006

Autophagy has been recognized as an important cellular process for at least 50 years; however, it is only with the recent identification of key regulators of autophagy (Atg genes) that we have begun a mechanistic exploration of its importance in cancer. Recent studies suggest that autophagy may be important in the regulation of cancer development and progression and in determining the response of tumor cells to anticancer therapy. However, the role of autophagy in these processes is complicated and may, depending on the circumstances, have diametrically opposite consequences for the tumor. In this article, we discuss recent discoveries regarding autophagy in cancer. (Cancer Res 2006; 66(19): 9349-51)
Antitumor Activity of an Oncolytic Adenovirus-Delivered Oncogene Small Interfering RNA
Authors: Zhang Yu-An , Nemunaitis John , Samuel Shirley K. , Chen Patrick , Shen Yuqiao , Tong Alex W.
Published: October 2006

Despite successes in animal models, cancer gene therapy with small interfering RNAs (siRNA) is hindered by the lack of an optimal delivery platform. We examined the applicability of the replication-competent, oncolytic adenovirus, ONYX-411, to deliver a mutant K-ras siRNA transgene to human cancer cells. Proof-of-principle studies showed an additive tumor growth–inhibitory response through siRNA-mediated K-ras knockdown and ONYX-411-mediated cancer cell lysis. A novel construct, termed Internavec (for interfering RNA vector), was generated by cloning a K-rasv12-specific siRNAras-4 hairpin construct under the control of the human H1 promoter into the deleted E3b region of ONYX-411. Internavec acquired an increase in potency of ∼10-fold in human cancer cells expressing the relevant K-rasv12 mutation (H79, H441, and SW480), as defined by a reduction in the effective dose needed to achieve 50% growth inhibition (ED50). Internavec remained attenuated in nonmalignant epithelial cells. Daily intratumoral injections of Internavec (five daily injections of 1 × 108 plaque-forming units) significantly reduced the growth of s.c. H79 pancreatic cancer xenografts in nu/nu mice by 85.5%, including complete growth suppression in three of five mice. Parental ONYX-411 or ONYX-411-siRNAGFP was markedly less effective (47.8% growth reduction, P = 0.03; and 44.1% growth reduction, P = 0.03, respectively). siRNAras transgene activity contributed to cell cycle blockage, increased apoptosis, and marked down-regulation of Ras signaling–related gene expression (AKT2, GSK3β, E2F2, and MAP4K5). These findings indicate that Internavec can generate a two-pronged attack on tumor cells through oncogene knockdown and viral oncolysis, resulting in a significantly enhanced antitumor outcome. (Cancer Res 2006; 66(19): 9736-43)
Tumor-Specific p73 Up-regulation Mediates p63 Dependence in Squamous Cell Carcinoma
Authors: DeYoung Maurice Phillip , Johannessen Cory M. , Leong Chee-Onn , Faquin William , Rocco James W. , Ellisen Leif W.
Published: October 2006

p63 is essential for normal epithelial development and is overexpressed in the vast majority of squamous cell carcinomas (SCC). Recent work had shown that ΔNp63α is essential for survival of SCC cells, raising the possibility that the p63 pathway may be an attractive therapeutic target in these tumors. Nevertheless, it is unknown whether a therapeutic window exists for inhibiting p63 in tumor cells versus normal epithelia. Here, we show that SCC cells are uniquely dependent on ΔNp63α for survival, unlike normal p63-expressing epithelial cells, and that dependence is mediated through tumor-specific up-regulation of the related protein p73. In normal primary human keratinocytes, we find that inhibition of endogenous p63 by RNA interference (RNAi) induces p21CIP1 expression, inhibits cell cycle progression, and ultimately promotes cellular senescence. In contrast, p63 inhibition in SCC cells induces proapoptotic bcl-2 family members and rapidly triggers apoptosis. Expression of p73 is low in uncultured basal keratinocytes but is markedly up-regulated in both SCC cell lines and primary tumors in vivo. Whereas p21CIP1 induction following loss of p63 in normal cells is independent of p53 and p73, both proapoptotic gene induction and cell death following p63 RNAi in tumor cells are p73 dependent. Finally, ectopic p73 expression in primary keratinocytes does not affect baseline cell proliferation but is sufficient to trigger cell death following loss of p63. Together, these findings define a specific molecular mechanism of p63 dependence through p73 up-regulation, and they provide a rationale for targeting the p63 pathway as a therapeutic strategy in SCCs. (Cancer Res 2006; 66(19): 9362-8)
Activation of Cancer Cell Migration and Invasion by Ectopic Synthesis of Coagulation Factor VII
Authors: Koizume Shiro , Jin Ming-Shou , Miyagi Etsuko , Hirahara Fumiki , Nakamura Yoshiyasu , Piao Jin-Hua , Asai Akio , Yoshida Akira , Tsuchiya Eiju , Ruf Wolfram , Miyagi Yohei
Published: October 2006

Blood coagulation factor VII (fVII) is physiologically synthesized in the liver and released into the blood. Binding of fVII to tissue factor (TF) at sites of vascular injury triggers coagulation and hemostasis. TF/fVIIa complex formation on the surface of cancer cells plays important roles in cancer biology. Although fVII is synthesized by hepatocellular carcinoma, it remained unclear how TF/fVIIa complex formation and promigratory signaling can occur for most other cancers in extravascular locations. Here, we show by reverse transcription-PCR analysis that nonhepatic cancer cell lines constitutively express fVII mRNA and that endogenously synthesized fVIIa triggers coagulation activation on these cells. fVIIa expression in cancer cells is inducible under hypoxic conditions and hypoxia-inducible factor-2α bound the promoter region of the FVII gene in chromatin immunoprecipitation analyses. Constitutive fVII expression in an ovarian cancer cell line enhanced both migration and invasion. Enhanced motility was blocked by anti-TF antibodies, factor Xa inhibition, and anti–protease-activated receptor-1 antibody treatment, confirming that TF/fVIIa stimulated migration by triggering cell signaling. This study shows that ectopic synthesis of fVII by cancer cells is sufficient to support proinvasive factor Xa–mediated protease-activated receptor-1 signaling and that this pathway is inducible under hypoxia. (Cancer Res 2006; 66(19): 9453-60)
The Differential Staurosporine-Mediated G1 Arrest in Normal versus Tumor Cells Is Dependent on the Retinoblastoma Protein
Authors: McGahren-Murray Mollianne , Terry Nicholas H.A. , Keyomarsi Khandan
Published: October 2006

Previously, we reported that breast cancer cells with retinoblastoma (pRb) pathway–defective checkpoints can be specifically targeted with chemotherapeutic agents, following staurosporine-mediated reversible growth inhibition in normal cells. Here we set out to determine if the kinetics of staurosporine-mediated growth inhibition is specifically targeted to the G1 phase of cells, and if such G1 arrest requires the activity of wild-type pRb. Normal human mammary epithelial and immortalized cells with intact pRb treated with low concentrations of staurosporine arrested in the G1 phase of the cell cycle, whereas pRb-defective cells showed no response. The duration of G1 and transition from G1 to S phase entry were modulated by staurosporine in Rb-intact cells. In pRb+ cells, but not in Rb− cells, low concentrations of staurosporine also resulted in a significant decrease in cyclin-dependent kinase 4 (CDK4) expression and activity. To directly assess the role of pRb in staurosporine-mediated G1 arrest, we subjected wild-type (Rb+/+) and pRb−/− mouse embryo fibroblasts (MEFs) to staurosporine treatments. Our results show that whereas Rb+/+ MEFs were particularly sensitive to G1 arrest mediated by staurosporine, pRb−/− cells were refractory to such treatment. Additionally, CDK4 expression was also inhibited in response to staurosporine only in Rb+/+ MEFs. These results were recapitulated in breast cancer cells treated with siRNA to pRb to down-regulate the pRb expression. Collectively, our data suggest that treatment of cells with nanomolar concentrations of staurosporine resulted in down-regulation of CDK4, which ultimately leads to G1 arrest in normal human mammary epithelial and immortalized cells with an intact pRb pathway, but not in pRb-null/defective cells. (Cancer Res 2006; 66(19): 9744-53)
In vivo and In vitro Evidence for Transforming Growth Factor-β1-Mediated Epithelial to Mesenchymal Transition in Esophageal Adenocarcinoma
Authors: Rees Jonathan R.E. , Onwuegbusi Benjamin A. , Save Vicki E. , Alderson Derek , Fitzgerald Rebecca C.
Published: October 2006

There is increasing evidence that epithelial to mesenchymal transition (EMT) is involved in cancer progression. Because local invasion and metastasis occurs early in the pathogenesis of esophageal adenocarcinoma, we hypothesized that EMT may be important in this disease. Using immunohistochemistry in a well-characterized set of adenocarcinoma tissues, we showed down-regulation of epithelial markers (E-cadherin and cytokeratin 18) and up-regulation of mesenchymal markers (vimentin and α-smooth muscle actin) with concomitant transforming growth factor-β1 (TGF-β1) expression at the invasive margin compared with the central tumor. A panel of esophageal cell lines was examined for the ability of TGF-β1 to induce EMT in vitro. TE7 cells were selected as a model because TGF-β1 (0-5 ng/mL) treatment induced morphologic and molecular expression changes suggestive of EMT. In TE7 cells, these TGF-β1-induced changes were reversed by 100 ng/mL of bone morphogenetic protein 7 (BMP7), another member of the TGF-β1 superfamily. EMT was mediated via canonical TGF-β1 signaling with concomitant up-regulation of SMAD-interacting protein 1. Alterations in functional variables (aggregation, wounding, motility, and invasion) following TGF-β1 treatment were consistent with a more invasive phenotype. These functional changes were reversed by BMP7 and SMAD4 RNA interference in vitro. These data suggest that TGF-β1-mediated EMT may be relevant in esophageal carcinogenesis. (Cancer Res 2006; 66(19): 9583-90)
Stop Hypertension With the Acupuncture Research Program (SHARP)
Authors: Macklin Eric A. , Wayne Peter M. , Kalish Leslie A. , Valaskatgis Peter , Thompson James , Pian-Smith May C.M. , Zhang Qunhao , Stevens Stephanie , Goertz Christine , Prineas Ronald J. , Buczynski Beverly , Zusman Randall M.
Published: October 2006

Case studies and small trials suggest that acupuncture may effectively treat hypertension, but no large randomized trials have been reported. The Stop Hypertension with the Acupuncture Research Program pilot trial enrolled 192 participants with untreated blood pressure (BP) in the range of 140/90 to 179/109 mm Hg. The design of the trial combined rigorous methodology and adherence to principles of traditional Chinese medicine. Participants were weaned off antihypertensives before enrollment and were then randomly assigned to 3 treatments: individualized traditional Chinese acupuncture, standardized acupuncture at preselected points, or invasive sham acupuncture. Participants received ≤12 acupuncture treatments over 6 to 8 weeks. During the first 10 weeks after random assignment, BP was monitored every 14 days, and antihypertensives were prescribed if BP exceeded 180/110 mm Hg. The mean BP decrease from baseline to 10 weeks, the primary end point, did not differ significantly between participants randomly assigned to active (individualized and standardized) versus sham acupuncture (systolic BP: −3.56 versus −3.84 mm Hg, respectively; 95% CI for the difference: −4.0 to 4.6 mm Hg;
P
=0.90; diastolic BP: −4.32 versus −2.81 mm Hg, 95% CI for the difference: −3.6 to 0.6 mm Hg;
P
=0.16). Categorizing participants by age, race, gender, baseline BP, history of antihypertensive use, obesity, or primary traditional Chinese medicine diagnosis did not reveal any subgroups for which the benefits of active acupuncture differed significantly from sham acupuncture. Active acupuncture provided no greater benefit than invasive sham acupuncture in reducing systolic or diastolic BP.
Implication of Chromosome 18 in Hypertension by Sibling Pair and Association Analyses
Authors: Guzmán Blanca , Cormand Bru , Ribasés Marta , González-Núñez Daniel , Botey Albert , Poch Esteban
Published: October 2006

This study aims to test the implication of regions on chromosomes 9, 17, and 18 in essential hypertension (EH) by combining sibling-pair linkage analysis and case–control association studies. The selection of these chromosomal regions is based on previous evidence of their implication in EH or in related phenotypes by comparative genomics in several rat models and from genome-wide linkage studies in humans. For the affected sibling-pair linkage analysis, 27 microsatellite markers were genotyped in 56 pedigrees from Spain with hypertensive sibling pairs. Linkage analysis showed significant excess allele sharing at the D18S474 marker on 18q21.1, as shown by maximum likelihood of allele sharing methods (logarithm of odds=3.24;
P
=0.00011) and nonparametric linkage calculations (nonparametric linkage=3.32;
P
=0.00044). On the contrary, no significant results with any of the markers analyzed on chromosomes 9 and 17 were obtained. We further focused on the Ring finger and KH domain containing 2 (
RKHD2
) gene located 6 Kb distal from D18S474 and performed a case–control association study based on linkage disequilibrium in 112 hypertensive patients and 156 control subjects. We selected 2
RKHD2
-tagged single nucleotide polymorphisms, rs1941958 and rs1893379, covering, in terms of linkage disequilibrium, the entire gene, and observed a significant overrepresentation of the rs1941958G-rs1893379T
RKHD2
haplotype in the group of hypertensive patients in comparison with controls (2
P
=0.0004; odds ratio: 2.32). We also detected epistatic effects between the 2
RKHD2
single nucleotide polymorphisms (2
P
=0.002; odds ratio: 2.48). Our data confirm the implication of chromosome 18 in EH and support a contribution of
RKHD2
to the genetic susceptibility of this complex phenotype.
Late-Onset Endothelin-A Receptor Blockade Reduces Podocyte Injury in Homozygous Ren-2 Rats Despite Severe Hypertension
Authors: Opočenský Martin , Kramer Herbert J. , Bäcker Angela , Vernerová Zdenka , Eis Václav , Červenka Luděk , Čertíková Chábová Věra , Tesař Vladimír , Vaněčková Ivana
Published: October 2006

We have recently found in male homozygous hypertensive Ren-2 transgenic rats (TGRs) fed a high-salt diet that early onset selective endothelin (ET) A (ET
A
) or nonselective ET
A
/ET B (ET
B
) receptor blockade improved survival rate and reduced proteinuria, glomerulosclerosis, and cardiac hypertrophy, whereas selective ET
A
receptor blockade also significantly attenuated the rise in blood pressure. Because antihypertensive therapy in general is known to be more efficient when started at early age, our study was performed to determine whether onset of ET receptor blockade at a later age in animals with established hypertension will have similar protective effects as does early-onset therapy. Male homozygous TGRs and age-matched normotensive Hannover Sprague–Dawley rats were fed a high-salt diet between days 51 and 90 of age. TGRs received vehicle (untreated), the selective ET
A
receptor blocker atrasentan (ABT-627), or the nonselective ET
A
/ET
B
receptor blocker bosentan. Survival rates in untreated and bosentan-treated TGRs were 50% and 64%, respectively, whereas with atrasentan, survival rate of TGR was 96%, thus, similar to 93% in Hannover Sprague–Dawley rats. From day 60 on, systolic blood pressure in atrasentan-treated TGRs was transiently lower (
P
<0.05) than in untreated or bosentan-treated TGRs. Glomerular podocyte injury was substantially reduced with atrasentan treatment independent of severe hypertension and strongly correlated with survival (
P
<0.001). Our data indicate that in homozygous TGR ET receptors play an important role also in established hypertension. Selective ET
A
receptor blockade not only reduces podocyte injury and end-organ damage but also improves growth and survival independently of hypertension.
The Chemokine and Chemokine Receptor Profile of Infiltrating Cells in the Wall of Arteries With Cardiac Allograft Vasculopathy Is Indicative of a Memory T–Helper 1 Response
Authors: van Loosdregt Jorg , van Oosterhout Matthijs F.M. , Bruggink Annette H. , van Wichen Dick F. , van Kuik Joyce , de Koning Erica , Baan Carla C. , de Jonge Nicolaas , Gmelig-Meyling Frits H.J. , de Weger Roel A.
Published: October 2006

Background—

Despite improvement in short-term patient survival after heart transplantation (HTx), long-term survival rates have not improved much, mainly because of cardiac allograft vasculopathy (CAV). Cytokines and chemokines are considered to play an important role in CAV development.

Methods and Results—

We focused on coronary arteries of HTx patients and made an inventory of the infiltrating cells and the expression of cytokines as well as chemokines and chemokine receptors (C+CR) in the different layers of the vessel wall with CAV. Tissue slides were stained for a variety of cell markers (CD3, CD4, CD8, CD20, CD68, CD79a), chemokines (monokine induced by interferon [MIG], interferon-inducible protein 10 [IP-10], interferon-inducible T cell-α chemoattractant [ITAC], RANTES [regulated on activation normal T cell expressed and secreted], and fractalkine), and chemokine receptors (CXCR3, CCR5, and CX3CR1). In reference coronary arteries (not transplanted), almost no infiltrating cells were found, and in transplanted hearts with CAV (HTx+CAV), a large number of T cells were observed (CD4:CD8=2:1), mainly localized in the neointima and adventitia. Most of these T cells appeared to be activated (human leukocyte antigen DR positive). Coronary arteries from transplanted hearts without CAV (HTx−CAV), HTx+CAV, and references were also analyzed for cytokine and C+CR mRNA expression with the use of quantitative polymerase chain reaction. Interferon-γ was highly expressed in HTx+CAV compared with HTx−CAV. Interleukin-4 and interleukin-10 were expressed at the same level in both HTx groups and references. In HTx+CAV, all C+CR, but especially the T–helper 1 (TH1) C+CR, were more abundant than in the HTx−CAV and references. However, TH2 CCR4 expression did not differ significantly between both HTx groups.

Conclusions—

In coronary arteries with CAV, most T cells are CD4
+
and express human leukocyte antigen DR. These activated TH cells are mainly memory TH1 cells on the basis of their C+CR profile and cytokine expression.
Drawbacks and Prognostic Value of Formulas Estimating Renal Function in Patients With Chronic Heart Failure and Systolic Dysfunction
Authors: Smilde Tom D.J. , van Veldhuisen Dirk J. , Navis Gerjan , Voors Adriaan A. , Hillege Hans L.
Published: October 2006

Background—

Renal function is an important risk marker for morbidity and mortality in chronic heart failure (CHF) and is often estimated with the use of creatinine-based formulas. However, these formulas have never been validated in a wide range of CHF patients. We validated 3 commonly used formulas estimating glomerular filtration rate (GFR) with true GFR in CHF patients. Furthermore, we compared the prognostic value of these formulas for cardiovascular outcome with that of true GFR during 12 months of follow-up.

Methods and Results—

In 110 CHF patients (age, 57±11.7 years; left ventricular ejection fraction, 0.27±0.09; NYHA class, 2.5±0.9), we measured
125
I-iothalamate clearance. Cockcroft-Gault (GFR
cg
), Modification of Diet in Renal Disease (MDRD), and simplified MDRD (sMDRD) equations were used as creatinine-based renal function estimations. Furthermore, 24-hour creatinine clearance (CrCl) was determined. CrCl and GFR
cg
were the most accurate. MDRD was most precise formula, although it was also highly biased. All formulas overestimated in the lower ranges and underestimated in the upper ranges of the GFR corrected for body surface area. The predictive performance of the formulas was best in severe CHF (NYHA classes III and IV). The prognostic value of CrCl and MDRD for cardiovascular outcome was comparable to that of GFR, the sMDRD was slightly less, and the GFR
cg
had a significantly worse prognostic value.

Conclusions—

In the more severe ranges of CHF, creatinine-based formulas and CrCl corrected for body surface area appeared to be more precise and accurate in estimating true GFR corrected for body surface area. The MDRD formula is the most precise and has a good prognostic value, whereas the sMDRD is slightly less accurate but uses fewer parameters, which makes this formula a practical alternative in clinical practice.
Direct Vascular Effects of Protease-Activated Receptor Type 1 Agonism In Vivo in Humans
Authors: Gudmundsdóttir Ingibjörg J. , Megson Ian L. , Kell Jillian S. , Ludlam Christopher A. , Fox Keith A.A. , Webb David J. , Newby David E.
Published: October 2006

Background—

Protease-activated receptor type 1 (PAR-1) has been proposed as the principal thrombin receptor in humans, although its actions in vivo have not been defined. The aim of the present study was to determine the direct vascular actions of PAR-1 agonism in humans.

Methods and Results—

Dorsal hand vein diameter was measured by the Aellig technique in 14 healthy volunteers during local intravenous SFLLRN (PAR-1 agonist; 0.05 to 15 nmol/min) and SLIGKV (PAR-2 agonist; 1.6 to 160 nmol/min) infusions. The venous effects of SFLLRN were further assessed in the presence or absence of norepinephrine or the glycoprotein IIb/IIIa antagonist tirofiban. Forearm blood flow was measured by venous occlusion plethysmography in 16 volunteers during infusion of SFLLRN (1 to 50 nmol/min), SLIGKV (160 to 800 nmol/min), and the endothelium-dependent vasodilator bradykinin (100 to 1000 pmol/min). Platelet-monocyte binding (a sensitive measure of platelet activation) and plasma tissue plasminogen activator (tPA), plasminogen-activator inhibitor 1, and von Willebrand factor concentrations were measured at intervals throughout the study. SFLLRN caused dose-dependent venoconstriction (
P
<0.001) that was unaffected by norepinephrine or tirofiban co-infusion. In forearm resistance vessels, SFLLRN increased forearm blood flow (
P
<0.001), tPA release (
P
<0.001), and platelet-monocyte binding (
P
<0.0001) without affecting plasma plasminogen-activator inhibitor 1 or von Willebrand factor concentrations. SLIGKV caused venous (
P
<0.001) and arterial (
P
<0.01) dilatation without tPA release.

Conclusions—

We have demonstrated that PAR-1 agonism causes platelet activation, venous constriction, arterial dilatation, and tPA release in vivo in humans. These unique and contrasting effects provide important insights into the physiological and pathophysiological role of thrombin in the human venous and arterial circulations.
Belated Decolonization and UN Politics against the Backdrop of the Cold War: Portugal, Britain, and Guinea-Bissau's Proclamation of Independence, 1973–1974
Authors: MacQueen Norrie
Published: October 2006

When a guerrilla movement opposing Portuguese rule in Guinea-Bissau issued a unilateral declaration of independence in September 1973, it created a dilemma for Portugal's allies in the North Atlantic Treaty Organization (NATO). Although Britain, like other NATO countries, wanted to keep Portugal within the alliance, British officials were exasperated by the Portuguese regime's refusal to let go of its colonies in Africa. When the United Nations (UN) took up the issue of Guinea-Bissau, Britain came under intense pressure from Portugal to proffer its support. Declassified documents from the British National Archives underscore the difficulties that ensued. British officials were mindful of their relationship with Portugal, but they were unsure of the intentions of the other Western permanent members of the UN Security Council and were worried about damaging Britain's broader position in Africa. This dilemma was not resolved until April 1974 when a military coup in Lisbon led to the Portuguese withdrawal from Guinea-Bissau.
Strategy, Ideology, and Human Rights: Jimmy Carter Confronts the Left in Central America, 1979–1981
Authors: Soares John A.
Published: October 2006

This article discusses the Carter administration's policies toward Nicaragua and El Salvador after the Sandinistas took power in Nicaragua in July 1979. These policies were influenced by the widespread perception at the time that Marxist revolutionary forces were in the ascendance and the United States was in retreat. Jimmy Carter was trying to move away from traditional American “interventionism” in Latin America, but he was also motivated by strategic concerns about the perception of growing Soviet and Cuban strength, ideological concerns about the spread of Marxism-Leninism, and political-humanitarian concerns about Marxist-Leninist regimes' systematic violations of human rights.
Containment Strategies in Perspective
Authors: Jervis Robert L.
Published: October 2006

John L. Gaddis's classic 1982 book Strategies of Containment, now out in a revised and expanded edition, characterizes the Cold War strategies of successive U.S. administrations as either symmetric or asymmetric. The new edition of the book retains this distinction and applies it to the administrations of Jimmy Carter and Ronald Reagan. Gaddis incorporates a few findings from research that has appeared since 1982, but the original text has undergone fewer revisions than one might have expected. Gaddis's general approach, and many of his specific claims, are bound to provoke objections, but historians and political scientists will find his analysis stimulating and provocative.
Feedbacks of Vegetation on Summertime Climate Variability over the North American Grasslands. Part I: Statistical Analysis
Authors: Wang Weile , Anderson Bruce T. , Phillips Nathan , Kaufmann Robert K. , Potter Christopher , Myneni Ranga B.
Published: October 2006

Feedbacks of vegetation on summertime climate variability over the North American Grasslands are analyzed using the statistical technique of Granger causality. Results indicate that normalized difference vegetation index (NDVI) anomalies early in the growing season have a statistically measurable effect on precipitation and surface temperature later in summer. In particular, higher means and/or decreasing trends of NDVI anomalies tend to be followed by lower rainfall but higher temperatures during July through September. These results suggest that initially enhanced vegetation may deplete soil moisture faster than normal and thereby induce drier and warmer climate anomalies via the strong soil moisture–precipitation coupling in these regions. Consistent with this soil moisture–precipitation feedback mechanism, interactions between temperature and precipitation anomalies in this region indicate that moister and cooler conditions are also related to increases in precipitation during the preceding months. Because vegetation responds to soil moisture variations, interactions between vegetation and precipitation generate oscillations in NDVI anomalies at growing season time scales, which are identified in the temporal and the spectral characteristics of the precipitation–NDVI system. Spectral analysis of the precipitation–NDVI system also indicates that 1) long-term interactions (i.e., interannual and longer time scales) between the two anomalies tend to enhance one another, 2) short-term interactions (less than 2 months) tend to damp one another, and 3) intermediary-period interactions (4–8 months) are oscillatory. Together, these results support the hypothesis that vegetation may influence summertime climate variability via the land–atmosphere hydrological cycles over these semiarid grasslands.
Feedbacks of Vegetation on Summertime Climate Variability over the North American Grasslands. Part II: A Coupled Stochastic Model
Authors: Wang Weile , Anderson Bruce T. , Entekhabi Dara , Huang Dong , Kaufmann Robert K. , Potter Christopher , Myneni Ranga B.
Published: October 2006

A coupled linear model is derived to describe interactions between anomalous precipitation and vegetation over the North American Grasslands. The model is based on biohydrological characteristics in the semiarid environment and has components to describe the water-related vegetation variability, the long-term balance of soil moisture, and the local soil–moisture–precipitation feedbacks. Analyses show that the model captures the observed vegetation dynamics and characteristics of precipitation variability during summer over the region of interest. It demonstrates that vegetation has a preferred frequency response to precipitation forcing and has intrinsic oscillatory variability at time scales of about 8 months. When coupled to the atmospheric fields, such vegetation signals tend to enhance the magnitudes of precipitation variability at interannual or longer time scales but damp them at time scales shorter than 4 months; the oscillatory variability of precipitation at the growing season time scale (i.e., the 8-month period) is also enhanced. Similar resonance and oscillation characteristics are identified in the power spectra of observed precipitation datasets. The model results are also verified using Monte Carlo experiments.
Atmospheric Forcing on the Barents Sea Winter Ice Extent
Authors: Sorteberg Asgeir , Kvingedal Børge
Published: October 2006

The atmospheric forcing on the Barents Sea ice extent during winter [December–February (DJF)] has been investigated for the period 1967–2002. The time series for the sea ice extent is updated and includes the winter of 2005, which marks a new record low in the wintertime Barents Sea ice extent, and a linear trend of −3.5% decade−1 in the ice extent was found. Covariability between the Barents Sea ice extent and the atmospheric mean seasonal flow and the synoptic cyclones has been discussed separately. For the mean flow, linear correlations and regression analysis reveal that anomalous northerly (southerly) winds prevail in the Nordic Seas during winters with extensive (sparse) Barents Sea ice extent. Some of the variability in the mean flow is captured by the North Atlantic Oscillation (NAO); however, the wintertime link between the Barents Sea ice extent and the NAO is moderate. By studying the cyclone activity in the high-latitude Northern Hemisphere using a dataset of individual cyclones, two regions that influence the wintertime Barents Sea ice extent were identified. The variability in the northward-moving cyclones traveling into the Arctic over East Siberia was found to covary strongly with the Barents Sea ice extent. The main mechanism is believed to be the change in the Arctic winds and in ice advection connected to the cyclones. In addition, cyclone activity of northward-moving cyclones over the western Nordic Seas was identified to strongly influence the Barents Sea ice extent. This relationship was particularly strong on decadal time scales and when the ice extent lagged the cyclone variability by 1–2 yr. The lag indicates that the mechanism is related to the cyclones’ ability to modulate the inflow of Atlantic water into the Nordic Seas and the transport time of oceanic heat anomalies from the Nordic Seas into the Barents Sea. Multiple regression indicates that the two mechanisms may explain (or at least covary with) 46% of the wintertime Barents Sea variance over the 1967–2002 period and that 79% of the decadal part of the ice variability may be predicted 2 yr ahead using information about the decadal cyclone variability in the Nordic Seas.
Detection of prokaryotic promoters from the genomic distribution of hexanucleotide pairs
Authors: Jacques Pierre-Étienne , Rodrigue Sébastien , Gaudreau Luc , Goulet Jean , Brzezinski Ryszard
Published: October 2006

Background

In bacteria, sigma factors and other transcriptional regulatory proteins recognize DNA patterns upstream of their target genes and interact with RNA polymerase to control transcription. As a consequence of evolution, DNA sequences recognized by transcription factors are thought to be enriched in intergenic regions (IRs) and depleted from coding regions of prokaryotic genomes.

Results

In this work, we report that genomic distribution of transcription factors binding sites is biased towards IRs, and that this bias is conserved amongst bacterial species. We further take advantage of this observation to develop an algorithm that can efficiently identify promoter boxes by a distribution-dependent approach rather than a direct sequence comparison approach. This strategy, which can easily be combined with other methodologies, allowed the identification of promoter sequences in ten species and can be used with any annotated bacterial genome, with results that rival with current methodologies. Experimental validations of predicted promoters also support our approach.

Conclusion

Considering that complete genomic sequences of over 1000 bacteria will soon be available and that little transcriptional information is available for most of them, our algorithm constitutes a promising tool for the prediction of promoter sequences. Importantly, our methodology could also be adapted to identify DNA sequences recognized by other regulatory proteins.
Differential expression of WNT4 in testicular and ovarian development in a marsupial
Authors: Yu Hongshi , Pask Andrew J , Shaw Geoffrey , Renfree Marilyn B
Published: October 2006

Background

WNT4 is a key regulator of gonadal differentiation in humans and mice, playing a pivotal role in early embryogenesis. Using a marsupial, the tammar wallaby, in which most gonadal differentiation occurs after birth whilst the young is in the pouch, we show by quantitative PCR during early testicular and ovarian development that WNT4 is differentially expressed ingonads.

Results

Before birth, WNT4 mRNA expression was similar in indifferent gonads of both sexes. After birth, in females WNT4 mRNA dramatically increased during ovarian differentiation, reaching a peak by day 9–13 post partum (pp) when the ovarian cortex and medulla are first distinguishable. WNT4 protein was localised in the ovarian cortex and at the medullary boundary. WNT4 mRNA then steadily decreased to day 49, by which time all the female germ cells have entered meiotic arrest. In males, WNT4 mRNA was down-regulated in testes immediately after birth, coincident with the time that seminiferous cords normally form, and rose gradually after day 8. By day 49, when testicular androgen production normally declines, WNT4 protein was restricted to the Leydig cells.

Conclusion

This is the first localisation of WNT4 protein in developing gonads and is consistent with a role for WNT4 in steroidogenesis. Our data provide strong support for the suggestion that WNT4 not only functions as an anti-testis gene during early development, but is also necessary for later ovarian and testicular function.
Stem-loop structures in prokaryotic genomes
Authors: Petrillo Mauro , Silvestro Giustina , Di Nocera Pier Paolo , Boccia Angelo , Paolella Giovanni
Published: October 2006

Background

Prediction of secondary structures in the expressed sequences of bacterial genomes allows to investigate spontaneous folding of the corresponding RNA. This is particularly relevant in untranslated mRNA regions, where base pairing is less affected by interactions with the translation machinery. Relatively large stem-loops significantly contribute to the formation of more complex secondary structures, often important for the activity of sequence elements controlling gene expression.

Results

Systematic analysis of the distribution of stem-loop structures (SLSs) in 40 wholly-sequenced bacterial genomes is presented. SLSs were searched as stems measuring at least 12 bp, bordering loops 5 to 100 nt in length. G-U pairing in the stems was allowed. SLSs found in natural genomes are constantly more numerous and stable than those expected to randomly form in sequences of comparable size and composition. The large majority of SLSs fall within protein-coding regions but enrichment of specific, non random, SLS sub-populations of higher stability was observed within the intergenic regions of the chromosomes of several species. In low-GC firmicutes, most higher stability intergenic SLSs resemble canonical rho-independent transcriptional terminators, but very frequently feature at the 5'-end an additional A-rich stretch complementary to the 3' uridines. In all species, a clearly biased SLS distribution was observed within the intergenic space, with most concentrating at the 3'-end side of flanking CDSs. Some intergenic SLS regions are members of novel repeated sequence families.

Conclusion

In depth analysis of SLS features and distribution in 40 different bacterial genomes showed the presence of non random populations of such structures in all species. Many of these structures are plausibly transcribed, and might be involved in the control of transcription termination, or might serve as RNA elements which can enhance either the stability or the turnover of cotranscribed mRNAs. Three previously undescribed families of repeated sequences were found in Yersiniae, Bordetellae and Enterococci.
Progressive ganglion cell loss and optic nerve degeneration in DBA/2J mice is variable and asymmetric
Authors: Schlamp Cassandra L , Li Yan , Dietz Joel A , Janssen Katherine T , Nickells Robert W
Published: October 2006

Background

Glaucoma is a chronic neurodegenerative disease of the retina, characterized by the degeneration of axons in the optic nerve and retinal ganglion cell apoptosis. DBA/2J inbred mice develop chronic hereditary glaucoma and are an important model system to study the molecular mechanisms underlying this disease and novel therapeutic interventions designed to attenuate the loss of retinal ganglion cells. Although the genetics of this disease in these mice are well characterized, the etiology of its progression, particularly with respect to retinal degeneration, is not. We have used two separate labeling techniques, post-mortem DiI labeling of axons and ganglion cell-specific expression of the βGeo reporter gene, to evaluate the time course of optic nerve degeneration and ganglion cell loss, respectively, in aging mice.

Results

Optic nerve degeneration, characterized by axon loss and gliosis is first apparent in mice between 8 and 9 months of age. Degeneration appears to follow a retrograde course with axons dying from their proximal ends toward the globe. Although nerve damage is typically bilateral, the progression of disease is asymmetric between the eyes of individual mice. Some nerves also exhibit focal preservation of tracts of axons generally in the nasal peripheral region. Ganglion cell loss, as a function of the loss of βGeo expression, is evident in some mice between 8 and 10 months of age and is prevalent in the majority of mice older than 10.5 months. Most eyes display a uniform loss of ganglion cells throughout the retina, but many younger mice exhibit focal loss of cells in sectors extending from the optic nerve head to the retinal periphery. Similar to what we observe in the optic nerves, ganglion cell loss is often asymmetric between the eyes of the same animal.

Conclusion

A comparison of the data collected from the two cohorts of mice used for this study suggests that the initial site of damage in this disease is to the axons in the optic nerve, followed by the subsequent death of the ganglion cell soma.
Employment status and differences in the one-year coverage of physician visits: different needs or unequal access to services?
Authors: Virtanen Pekka , Kivimäki Mika , Vahtera Jussi , Koskenvuo Markku
Published: October 2006

Background

The dichotomy employed vs. unemployed is still a relevant, but rather crude measure of status in current labour markets. Also, studies concerning the association of employment status with health have to specify the type of the employment as well as the characteristics of the unemployment. This study aims to reveal differences and potential inequalities in physician visits among seven groups in the core-periphery structures of the labour markets.

Methods

A total of 16 000 Finns responded to a postal survey in 2003. Their visits to physicians in public primary health care, occupational health care, private health services, hospital outpatient clinics and dental care services during previous year were measured as indicators of service utilisation. Participants were classified as employees having a permanent or fixed-term and full-time or part-time contract and as those experiencing short-term, prolonged or long-term unemployment. Differences in the one-year coverage of physician visits between these groups of employees were analysed using logistic regression analyses where differences in the need for services were controlled for by including demographics and self-rated health assessments in the models.

Results

Permanently employed respondents had visited a physician most often, and the need-adjusted regression models showed significantly lower odds ratios for a visit among fixed-term employees (OR 0.65, 95% CI 0.53–0.81) and in particular among the long-term unemployed (OR 0.21, 95% CI 0.14–0.31). A stratified analysis according to health care sector showed the lowest odds ratios in occupational health care and private physicians (ORs between 0.05 and 0.73) and also low odds ratios for dentists (ORs between 0.45 and 0.91), whereas visits to public primary health care were more common among non-permanent employees and the unemployed (ORs between 1.46 and 2.39).

Conclusion

The use of physician services varies according to labour market status, being relatively low among the non-permanently employed and the unemployed. This underuse is emphasised when clinical need is taken into account. The main reasons for the variance evidently lie in the structures of the Finnish health service system. The result may indicate non-optimal health care of the population on the periphery of the labour market, but it may also reflect the importance of employment status as a context for need and the decision to visit a physician.
In vitro susceptibilities of Brucella melitensis isolates to eleven antibiotics
Authors: Turkmani Aun , Ioannidis Alexandros , Christidou Athanasia , Psaroulaki Anna , Loukaides Feidias , Tselentis Yiannis
Published: October 2006

Background

Brucellosis is an endemic disease present in many countries worldwide, but it is rare in Europe and North America. Nevertheless brucella is included in the bacteria potentially used for bioterrorism. The aim of this study was the investigation of the antibiotic susceptibility profile of brucella isolates from areas of the eastern Mediterranean where it has been endemic.

Methods

The susceptibilities of 74 Brucella melitensis isolates derived from clinical samples (57) and animal products (17) were tested in vitro. The strains originate from Crete (59), Cyprus (10), and Syria (5). MICs of tetracycline, rifampicin, streptomycin, gentamicin, norfloxacin, ciprofloxacin, levofloxacin, trimethoprim/sulfamethoxazole, ampicillin, amoxicillin/clavulanic acid, and erythromycin were detected by E-test method. The NCCLS criteria for slow growing bacteria were considered to interpret the results.

Results

All the isolates were susceptible to tetracycline, streptomycin, gentamicin, ciprofloxacin, norfloxacin, and levofloxacin. Two isolates presented reduced susceptibility to rifampicin (MIC value: 1.5 mg/l) and eight to SXT (MIC values: 0.75–1.5 mg/l). Erythromycin had the highest (4 mg/l) MIC90value and both norfloxacin and erythromycin the highest (1.5 mg/l) MIC50 value.

Conclusion

Brucella isolates remain susceptible in vitro to most antibiotics used for treatment of brucellosis. The establishment of a standardized antibiotic susceptibility method for Brucella spp would be useful for resistance determination in these bacteria and possible evaluation of bioterorism risks.