bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of Thrombopoietin in Mast Cell Differentiation
Authors: MIGLIACCIO ANNA RITA , RANA ROSA ALBA , VANNUCCHI ALESSANDRO M. , MANZOLI FRANCESCO A.
Published: July 2007

Abstract:  Mast cells are important elements of the body response to foreign antigens, being those represented either by small molecules (allergic response) or harbored by foreign microorganisms (response to parasite infection). These cells derive from hematopoietic stem/progenitor cells present in the marrow. However, in contrast with most of the other hematopoietic lineages, mast cells do not differentiate in the marrow but in highly vascularized extramedullary sites, such as the skin or the gut. Mast cell differentiation in the marrow is activated as part of the body response to parasites. We will review here the mast cell differentiation pathway and what is known of its major intrinsic and extrinsic control mechanisms. It will also be described that thrombopoietin, the ligand for the Mpl receptor, in addition to its pivotal rule in the control of thrombocytopoiesis and of hematopoietic stem/progenitor cell proliferation, exerts a regulatory function in mast cell differentiation. Some of the possible implications of this newly described biological activity of thrombopoietin will be discussed.
Biosafety and Selectable Markers
Authors: TITBALL RICHARD W. , SJOSTEDT ANDERS , PAVELKA MARTIN S. , NANO FRANCIS E.
Published: July 2007

Abstract: 
Francisella tularensis (F. tularensis) is one of the most infectious pathogens known. Although the disease caused by this bacterium is rarely fatal with appropriate antibiotic therapy, it is often severely debilitating. Laboratory work with F. tularensis poses a significant hazard, and it is essential that appropriate laboratory facilities, trained personnel, and suitable working practices are in place in any organization working with this pathogen. Work with human virulent strains should be carried out at containment level 3. Vaccines play an important potential role in the protection of individuals working with F. tularensis, but the live vaccine strain (LVS) vaccine is not currently licensed for use in humans. Because antibiotic therapy is central to the treatment of human tularemia, antibiotic resistance markers for use in genetic manipulation studies should be carefully selected.
The Structure and Function of Francisella Lipopolysaccharide
Authors: GUNN JOHN S. , ERNST ROBERT K.
Published: July 2007

Abstract:  A key factor in the biology of Francisella spp. is lipopolysaccharide (LPS). Francisella LPS has many unique structural properties and poorly activates proinflammatory responses due to its lack of interaction with toll‐like receptor 4 (TLR4). The LPS of this organism can be modified by various carbohydrates including glucose, mannose and galactosamine, which affect various aspects of virulence. Spontaneously occurring colony variants of F. tularensis have altered LPS. This altered LPS may account for the novel phenotypes of these variants that include effects on susceptibility to killing by normal human serum, intracellular survival and animal virulence. Mutants devoid of O‐antigen (directed mutants in O‐antigen biosynthetic genes) show reduced intracellular survival and mouse virulence. Thus, this surface component is important in F. tularensis pathogenesis, and the inability of the LPS to alarm the immune system coupled with its frequent modification/alteration likely aid the success of this pathogen during human infection.
Genetics and Genetic Manipulation in Francisella Tularensis
Authors: FRANK DARA W. , ZAHRT THOMAS C.
Published: July 2007

Abstract: 
Francisella tularensis is a gram‐negative coccobacillus and the etiological agent of tularemia. The limited knowledge regarding the interaction of F. tularensis with its host is due in part to the previous lack of tools for genetically manipulating the organism. During the past 10 years, the field of F. tularensis genetics has seen a rapid expansion. Plasmids capable of stable or conditional replication in Francisella have been constructed. Methods for the efficient introduction of DNA into Francisella have been developed or optimized. Genetic platforms and procedures for transposon mutagenesis and allelic exchange have been adapted for use in Francisella. Finally, selectable, counterselectable, and screenable genetic markers amenable for use in a variety of F. tularensis species, including highly virulent clinical isolates, have been described. Collectively, these advances have aided in the construction of defined Francisella mutants and helped investigators begin to define the mechanism(s) employed by these organisms to cause disease in the host. In this article, we describe the history of genetic manipulation in Francisella and summarize the current tools and techniques for conducting genetic studies in this organism.
Vaccines Against Francisella Tularensis
Authors: WAYNE CONLAN J. , OYSTON PETRA C.F.
Published: July 2007

Abstract: 
Francisella tularensis is one of the most pathogenic pathogens known, especially when disseminated as a small particle aerosol. Because of this, it was developed into a biological warfare agent by several states during the 20th century. Nowadays, concerns remain about the potential of this pathogen to cause widespread disease, tularemia, in the hands of terrorists. This has resurrected interest in methods to combat it. This article reviews the current status of vaccine development efforts against tularemia. To date most of our understanding of tularemia vaccine efficacy has been derived from the clinical and experimental use of a pragmatically attenuated live vaccine strain of F. tularensis subspecies holarctica. However, this vaccine which has been in existence for more than 50 years is still beset by regulatory issues that continue to hamper its licensure. These issues and possible solutions are highlighted, along with more modern molecular approaches to vaccine development against this highly virulent pathogen.
Type II Secretion and Type IV Pili of Francisella
Authors: FORSBERG ÅKE , GUINA TINA
Published: July 2007

Abstract: 
Francisella tularensis genomes encode homologues of type IV pili. Though several F. tularensis genes required for Tfp expression are homologous to genes required for type II secretion (T2S), these gene clusters mainly bear structural signatures that are typical of Tfp. There is preliminary evidence that different F. tularensis subspecies express Tfp‐like surface structures, but there are also some interesting differences between the subspecies. One difference between the nonpathogenic subspecies novicida (F. novicida) and the highly pathogenic type A strains is in sequence of one of the predicted pilin genes, pilA. In contrast, type B strains show several differences compared to type A strains, two predicted pilin genes and the pilT gene are pseudogenes, while pilA is identical to pilA that is encoded by the type A strains. This is likely significant as PilA contributes to virulence of type B strains while PilT is essential for Tfp retraction in other bacterial pathogens. Tfp‐mediated protein secretion is only evident in in vitro grown F. novicida. Surprisingly, secretion of several F. novicida proteins was dependent on pilA and other genes with postulated roles in Tfp expression. F. novicida secretion mutants were more virulent in the mouse infection model. Thus, in F. novicida, Tfp gene clusters serve both T2S and Tfp assembly and it is tempting to speculate that evolution of the pathogenic subspecies involved loss of functional T2S via structural changes of PilA and additional genes, including those that encode some of the Tfp‐secreted proteins.
Prognostic Value of p16 in Locally Advanced Prostate Cancer: A Study Based on Radiation Therapy Oncology Group Protocol 9202
Authors: Chakravarti Arnab , DeSilvio Michelle , Zhang Min , Grignon David , Rosenthal Seth , Asbell Sucha O. , Hanks Gerald , Sandler Howard M. , Khor Li-Yan , Pollack Alan , Shipley William
Published: July 2007

Purpose

Deregulation of the retinoblastoma (RB) pathway is commonly found in virtually all known human tumors. p16, the upstream regulator of RB, is among the most commonly affected member of this pathway. In the present study, we examined the prognostic value of p16 expression in men with locally advanced prostate cancer who were enrolled on Radiation Therapy Oncology Group protocol 9202.

Patients and Methods

RTOG 9202 was a phase III randomized study comparing long-term (LT) versus short-term (ST) androgen-deprivation therapy (AD). Of the 1,514 eligible cases, 612 patients had adequate tumor material for p16 analysis. Expression levels of p16 were determined by immunohistochemistry (IHC). IHC staining was scored quantitatively using an image analysis system.

Results

On multivariate analysis, intact p16 expression was significantly associated with decreased rate of distant metastases (P = .0332) when both STAD and LTAD treatment arms were considered together. For patients with intact (high levels of immunostaining) p16 (mean p16 index > 81.3%), LTAD plus radiotherapy (RT) significantly improved prostate cancer survival (PCS) compared with STAD plus RT (P = .0008) and reduced the frequency of distant metastasis (P = .0069) compared with STAD plus RT. In contrast, for patients with tumors demonstrating p16 loss (low levels of immunostaining, mean p16 index ≤ 81.3%), LTAD plus RT significantly improved biochemical no evidence of disease survival over STAD (P < .0001) primarily by decreasing the frequency of local progression (P = .02), as opposed to distant metastasis, which was the case in the high-p16 cohort.

Conclusion

Low levels of p16 on image analysis appear to be associated with a significantly higher risk of distant metastases among all study patients. p16 expression levels also appear to identify patients with locally advanced prostate cancer with distinct patterns of failure after LTAD.
Impact of Primary Prophylaxis With Granulocyte Colony-Stimulating Factor on Febrile Neutropenia and Mortality in Adult Cancer Patients Receiving Chemotherapy: A Systematic Review
Authors: Kuderer Nicole M. , Dale David C. , Crawford Jeffrey , Lyman Gary H.
Published: July 2007

Purpose

Randomized controlled trials (RCTs) of prophylactic granulocyte colony-stimulating factors (G-CSF) have demonstrated a significant reduction in febrile neutropenia (FN) after systemic chemotherapy. Several RCTs have been published recently that investigate the impact of G-CSF on mortality and relative dose-intensity (RDI).

Methods

A comprehensive systematic review and meta-analysis of all reported RCTs comparing primary prophylactic G-CSF with placebo or untreated controls in adult solid tumor and malignant lymphoma patients was undertaken without language restrictions, using electronic databases, conference proceedings, and hand-searching techniques. Two reviewers extracted data independently. Summary estimates of relative risk (RR) with 95% CIs were estimated based on the method of Mantel-Haenszel and DerSimonian and Laird.

Results

Seventeen RCTs were identified including 3,493 patients. For infection-related mortality, RR reduction with G-CSF compared with controls was 45% (RR = 0.55; 95% CI, 0.33 to 0.90; P = .018); for early mortality (all-cause mortality during chemotherapy period), it was 40% (RR = 0.60; 95% CI, 0.43 to 0.83; P = .002); and for FN, it was 46% (RR = 0.54; 95% CI, 0.43 to 0.67; P < .001). Average RDI was significantly higher in patients who received G-CSF compared with control patients (P < .001). Bone or musculoskeletal pain was reported in 10.4% of controls and 19.6% of G-CSF patients (RR = 4.03; 95% CI, 2.15 to 7.52; P < .001). Significant reductions in FN with G-CSF were observed in studies allowing secondary G-CSF prophylaxis in controls and in the three trials with concurrent prophylactic antibiotics in both treatment arms.

Conclusion

Prophylactic G-CSF reduces the risk of FN and early deaths, including infection-related mortality, while increasing RDI and musculoskeletal pain. There are insufficient data to assess the impact of G-CSF on disease-free and overall survival.
Common Germline Genetic Variation in Antioxidant Defense Genes and Survival After Diagnosis of Breast Cancer
Authors: Udler Miriam , Maia Ana-Teresa , Cebrian Arancha , Brown Clement , Greenberg David , Shah Mitul , Caldas Carlos , Dunning Alison , Easton Douglas , Ponder Bruce , Pharoah Paul
Published: July 2007

Purpose

The prognosis of breast cancer varies considerably among individuals, and inherited genetic factors may help explain this variability. Of particular interest are genes involved in defense against reactive oxygen species (ROS) because ROS are thought to cause DNA damage and contribute to the pathogenesis of cancer.

Patients and Methods

We examined associations between 54 polymorphisms that tag the known common variants (minor allele frequency > 0.05) in 10 genes involved in oxidative damage repair (CAT, SOD1, SOD2, GPX1, GPX4, GSR, TXN, TXN2, TXNRD1, and TXNRD2) and survival in 4,470 women with breast cancer.

Results

Two single nucleotide polymorphisms (SNPs) in GPX4 ( rs713041 and rs757229 ) were associated with all-cause mortality even after adjusting for multiple hypothesis testing (adjusted P = .0041 and P = .0035). These SNPs are correlated with each other (r2= 0.61). GPX4 rs713041 is located near the selenocysteine insertion sequence element in the GPX4 3′ untranslated region, and the rare allele of this SNP is associated with an increased risk of death, with a hazard ratio of 1.27 per rare allele carried (95% CI, 1.13 to 11.43). This effect was not attenuated after adjusting for tumor stage, grade, or estrogen receptor status. We found that the common allele is preferentially expressed in normal lymphocytes, normal breast, and breast tumors compared with the rare allele, but there were no differences in total levels of GPX4 mRNA across genotypes.

Conclusion

These data provide strong support for the hypothesis that common variation in GPX4 is associated with prognosis after a diagnosis of breast cancer.
Molecular Basis of Neonatal Diabetes in Japanese Patients
Authors: Suzuki Shigeru , Makita Yoshio , Mukai Tokuo , Matsuo Kumihiro , Ueda Osamu , Fujieda Kenji
Published: July 2007

Context: Neonatal diabetes mellitus (NDM) is classified clinically into a transient form (TNDM), in which insulin secretion recovers within several months, and a permanent form (PNDM), requiring lifelong medication. However, these conditions are genetically heterogeneous.

Objective: Our objective was to evaluate the contribution of the responsible gene and delineate their clinical characteristics.

Patients and Methods: The chromosome 6q24 abnormality and KCNJ11 and ABCC8 mutations were analyzed in 31 Japanese patients (16 with TNDM and 15 with PNDM). Moreover, FOXP3 and IPF1 mutations were analyzed in a patient with immune dysregulation, polyendocrinopathy, enteropathy X-linked syndrome and with pancreatic agenesis, respectively.

Results: A molecular basis for NDM was found in 23 patients: 6q24 in eleven, KCNJ11 in nine, ABCC8 in two, and FOXP3 in one. All the patients with the 6q24 abnormality and two patients with the KCNJ11 mutation proved to be TNDM. Five mutations were novel: two (p.A174G and p.C166Y) in KCNJ11, two (p.A90V and p.N1122D) in ABCC8, and one (p.P367L) in FOXP3. Comparing the 6q24 abnormality and KCNJ11 mutation, there were some significant clinical differences: the earlier onset of diabetes, the lower frequency of diabetic ketoacidosis at onset, and the higher proportion of the patients with macroglossia at initial presentation in the patients with 6q24 abnormality. In contrast, two patients with the KCNJ11 mutations manifested epilepsy and developmental delay.

Conclusions: Both the 6q24 abnormality and KCNJ11 mutation are major causes of NDM in Japanese patients. Clinical differences between them could provide important insight into the decision of which gene to analyze in affected patients first.
T6BP and NDP52 are myosin VI binding partners with potential roles in cytokine signalling and cell adhesion
Authors: Morriswood Brooke , Ryzhakov Grigory , Puri Claudia , Arden Susan D. , Roberts Rhys , Dendrou Calliope , Kendrick-Jones John , Buss Folma
Published: July 2007

Myosin VI has been implicated in many cellular processes including endocytosis, secretion, membrane ruffling and cell motility. We carried out a yeast two-hybrid screen and identified TRAF6-binding protein (T6BP) and nuclear dot protein 52 (NDP52) as myosin VI binding partners. Myosin VI interaction with T6BP and NDP52 was confirmed in vitro and in vivo and the binding sites on each protein were accurately mapped. Immunofluorescence and electron microscopy showed that T6BP, NDP52 and myosin VI are present at the trans side of the Golgi complex, and on vesicles in the perinuclear region. Although the SKICH domain in T6BP and NDP52 does not mediate recruitment into membrane ruffles, loss of T6BP and NDP52 in RNAi knockdown cells results in reduced membrane ruffling activity and increased stress fibre and focal adhesion formation. Furthermore, we observed in these knockdown cells an upregulation of constitutive secretion of alkaline phosphatase, implying that both proteins act as negative regulators of secretory traffic at the Golgi complex. T6BP was also found to inhibit NF-κB activation, implicating it in the regulation of TRAF6-mediated cytokine signalling. Thus myosin VI-T6BP interactions may link membrane trafficking pathways with cell adhesion and cytokine-dependent cell signalling.
Mechanical force modulates global gene expression and β-catenin signaling in colon cancer cells
Authors: Avvisato Christopher L. , Yang Xiang , Shah Salim , Hoxter Becky , Li Weiqun , Gaynor Richard , Pestell Richard , Tozeren Aydin , Byers Stephen W.
Published: July 2007

At various stages during embryogenesis and cancer cells are exposed to tension, compression and shear stress; forces that can regulate cell proliferation and differentiation. In the present study, we show that shear stress blocks cell cycle progression in colon cancer cells and regulates the expression of genes linked to the Wnt/β-catenin, mitogen-activated protein kinase (MAPK) and NFκB pathways. The shear stress-induced increase of the secreted Wnt inhibitor DKK1 requires p38 and activation of NFκB requires IκB kinase-β. Activation of β-catenin, important in Wnt signaling and the cause of most colon cancers, is inhibited by shear stress through a pathway involving laminin-5, α6β4 integrin, phosphoinositide 3-kinase (PI 3-kinase) and Rac1 coupled with changes in the distribution of dephosphorylated β-catenin. These data show that colon cancer cells respond to fluid shear stress by activation of specific signal transduction pathways and genetic regulatory circuits to affect cell proliferation, and indicate that the response of colon cancers to mechanical forces such as fluid shear stress should be taken into account in the management of the disease.
Removable Prostheses Revisited: Challenges for Primary Dental Care. 2. Partial Dentures
Authors: Preston Antony J
Published: July 2007

This is the second in a series of three papers. Its topic, the provision of removable prostheses, remains a significant aspect of primary dental care. In the recent past and in the near future, there have been and will be significant influences on how removable prostheses are provided for patients in the United Kingdom (UK). In this paper, the trends in partial edentulousness in the UK will be summarised and the important changes that are likely to influence removable partial denture provision will be outlined. The paper will then provide an update of clinical procedures in the provision of removable partial dentures. A third paper will consider overdentures.
A Comparison of the Attitudes and Beliefs of Professional Rugby Players from one Club and Parents of Children Playing Rugby at an Adjacent Amateur Club to the Wearing of Mouthguards
Authors: Chatterjee Mahua , Hilton Ian
Published: July 2007

Objective

To assess the knowledge that professional rugby players have with regard to the benefits of wearing an oral mouth-guard and the importance that they give to wearing the appliance during play, then to compare these views with those of the parents of children who are beginning to play the sport.

Design

Questionnaires and covering letters were sent to the parents of children who played rugby at Malton & Norton Rugby Union Football Club (RUFC), which has teams for all age groups from under 7–8 years to adult. Similar questionnaires were sent to the first team squad of Leeds Tykes, a Zurich Premiership rugby union club. The questionnaires asked a series of questions on the use of mouthguards and knowledge of their importance in the prevention of injuries.

Results

The overall response rate was 76%. Seventy-four of the 100 questionnaires sent to the parents and 25 of the 30 sent to the professional players were completed and returned. Both the professional rugby players and parents felt that mouthguards were essential when playing rugby. The professionals seemed to have a much greater understanding of the benefits that mouth-guards provided. Although parents agreed that children should begin to wear mouthguards as soon as possible, very few actually did. The barriers to providing mouth protection were mainly financial combined with the difficulties of taking the child to the dentist.

Conclusions

If the results from this small study are representative of the current situation, with regard to the wearing of mouth-guards by professional players and children, it appears that there is a need for all those involved to ensure that rugby-playing children wear mouthguards. Rugby clubs could consider the appointment of honorary dental advisers and devise systems to ensure that cost is not a factor in preventing children from wearing mouthguards.
A Simple and Robust Quantitative PCR Assay to Determine CYP21A2 Gene Dose in the Diagnosis of 21-Hydroxylase Deficiency
Authors: Parajes Silvia , Quinterio Celsa , Domínguez Fernando , Loidi Lourdes
Published: July 2007

Background: Correct diagnosis of 21-hydroxylase deficiency (21OHD) requires the identification of CYP21A2 gene deletions and CYP21A1P/CYP21A2 chimeric genes, which are disease-causing alleles, and gene duplications, which can lead to false-positive 21OHD allele results. Because lack of suitable CYP21A2 dosage assessment methods hampers correct 21OHD diagnosis, we developed a new assay based on the relative quantification of the CYP21A2 gene using the DSP gene as a reference.

Methods: The assay to determine CYP21A2 copy number is based on real-time PCR. The method also detects the presence of the CYP21A1P/CYP21A2 chimeric gene. We used a duplex PCR to coamplify the DSP gene, included as an internal control, along with CYP21A2. The difference in threshold cycles between CYP21A2 and DSP genes (ΔCt) was used to assess CYP21A2 copy number.

Results: The ΔCt values obtained from 24 samples used to set up the method clearly differentiated 3 nonoverlapping intervals, which corresponded to the number of CYP21A2 copies: −1.35 to −0.25 defined 2 gene copies, +0.20 to +2.00 defined 1 copy, and −2.50 to −1.50 defined 3 copies. With these intervals we were able to assess the gene copy number in 24 additional samples.

Conclusions: This new method for gene copy assessment detects homozygous and heterozygous CYP21A2 gene deletions, CYP21A1P/CYP21A2 chimeric genes, and gene duplications. Moreover, the method is robust, fast, and easy to use in a molecular diagnosis laboratory. This method together with CYP21A2 gene sequencing can provide a definitive system for the detection of almost all, common as well as rare, 21OHD alleles.
Characterization of Diabetic Nephropathy by Urinary Proteomic Analysis: Identification of a Processed Ubiquitin Form as a Differentially Excreted Protein in Diabetic Nephropathy Patients
Authors: Dihazi Hassan , Müller Gerhard A , Lindner Sandra , Meyer Markus , Asif Abdul R , Oellerich Michael , Strutz Frank
Published: July 2007

Background: Identification of markers for prediction of the clinical course of diabetic nephropathy remains a major challenge in disease management. We established a proteomics approach for identification of diabetic nephropathy-related biomarkers in urine.

Methods: We used SELDI-TOF mass spectrometry and SAX2 protein arrays to compare protein profiles from urine of 4 defined patient groups. Samples from patients with type 2 diabetes (DM; n = 45) without nephropathy and without microalbuminuria (DM-WNP), patients with DM with macro- or microalbuminuria (DM-NP; n = 38), patients with proteinuria due to nondiabetic renal disease (n = 34), and healthy controls (n = 45) were analyzed. Anionic exchange, reversed-phase fractionation, gel electrophoresis, and mass spectrometry were used to isolate and identify proteins with high discriminatory power.

Results: A protein with m/z 6188 (P <0.0000004) was strongly released in the urine of healthy controls, patients with proteinuria due to nondiabetic disease, and DM-WNP in contrast to DM-NP patients. An m/z 14 766 protein (P <0.00008) was selectively excreted in the urine of DM-NP patients, whereas the protein with m/z 11 774 (P <0.000004) was significantly excreted by patients with proteinuria and DM-NP. The m/z 11 774 and m/z 14 766 mass peaks were identified as β2-microglobulin and UbA52, a ubiquitin ribosomal fusion protein, respectively. The protein with m/z 6188 was identified as a processed form of ubiquitin.

Conclusion: The release of high amounts of UbA52 in urine of DM-NP patients could serve as a diagnostic marker, whereas the lack of the short form of ubiquitin raises interesting questions about the pathophysiology.
Reviews
Authors: Shaw Lisa , Norris David , Hipkins Danielle
Published: July 2007

Film's Musical Moments, Ian Conrich and Estella Tincknell (eds.), (2006) Edinburgh: Edinburgh University Press, 226 pp., ISBN 0-7486-2345-0 (pbk), 16.99; ISBN 0-7486-23442 (hbk), 50.00

The Cinema of the Balkans, Dina Iordanova (ed.), (2006) London and
New York: Wallflower Press, xvi + 291 pp., ISBN 1-904764-80-0 (pbk), 18.99; ISBN 1-904764-81-9 (hbk), 50.00

Marked women: prostitutes and prostitution in the cinema, Russell Campbell (2005) Madison and London: University of Wisconsin Press, 450 pp., ISBN 0-299-21254-8 (hbk,
65, pbk 24.95)
Sustained Neural Activity Patterns during Working Memory in the Human Medial Temporal Lobe
Authors: Axmacher Nikolai , Mormann Florian , Fernández Guillén , Cohen Michael X , Elger Christian E. , Fell Juergen
Published: July 2007

In contrast to classical findings that the medial temporal lobe (MTL) specifically underlies long-term memory, previous data suggest that MTL structures may also contribute to working memory (WM). However, the neural mechanisms by which the MTL supports WM have remained unknown. Here, we exploit intracranial EEG to identify WM-specific sustained activity patterns with the highest temporal and spatial resolution currently available in humans. Using a serial Sternberg paradigm, we found a positive shift of the direct current (DC) potential and a long-lasting decrease in MTL gamma-band activity during maintenance of a single item, reflective of a sustained reduction in neural activity. Maintenance of an increasing number of items elicited an incrementally negative shift of the DC potential and an increase in MTL gamma-band activity. In addition, the paradigm was conducted in healthy control subjects using functional magnetic resonance imaging. This confirmed that our results were not caused by pathological processes within the MTL, and that this region was indeed specifically activated during the task. Our results thus provide direct evidence for sustained neural activity patterns during working memory maintenance in the MTL, and show that these patterns depend on WM load.
The Secreted β-Amyloid Precursor Protein Ectodomain APPsα Is Sufficient to Rescue the Anatomical, Behavioral, and Electrophysiological Abnormalities of APP-Deficient Mice
Authors: Ring Sabine , Weyer Sascha W. , Kilian Susanne B. , Waldron Elaine , Pietrzik Claus U. , Filippov Mikhail A. , Herms Jochen , Buchholz Christian , Eckman Christopher B. , Korte Martin , Wolfer David P. , Müller Ulrike C.
Published: July 2007

It is well established that the proteolytic processing of the β-amyloid precursor protein (APP) generates β-amyloid (Aβ), which plays a central role in the pathogenesis of Alzheimer's disease (AD). In contrast, the physiological role of APP and of its numerous proteolytic fragments and the question of whether a loss of these functions contributes to AD are still unknown. To address this question, we replaced the endogenous APP locus by gene-targeted alleles and generated two lines of knock-in mice that exclusively express APP deletion variants corresponding either to the secreted APP ectodomain (APPsα) or to a C-terminal (CT) truncation lacking the YENPTY interaction motif (APPΔCT15). Interestingly, the ΔCT15 deletion resulted in reduced turnover of holoAPP, increased cell surface expression, and strongly reduced Aβ levels in brain, likely because of reduced processing in the endocytic pathway. Most importantly, we demonstrate that in both APP knock-in lines the expression of APP N-terminal domains either grossly attenuated or completely rescued the prominent deficits of APP knock-out mice, such as reductions in brain and body weight, grip strength deficits, alterations in circadian locomotor activity, exploratory activity, and the impairment in spatial learning and long-term potentiation. Together, our data suggest that the APP C terminus is dispensable and that APPsα is sufficient to mediate the physiological functions of APP assessed by these tests.
Fast Regulation of Axonal Growth Cone Motility by Electrical Activity
Authors: Ibarretxe Gaskon , Perrais David , Jaskolski Frédéric , Vimeney Alice , Mulle Christophe
Published: July 2007

Axonal growth cones are responsible for the correct guidance of developing axons and the establishment of functional neural networks. They are highly motile because of fast and continuous rearrangements of their actin-rich cytoskeleton. Here we have used live imaging of axonal growth cones of hippocampal neurons in culture and quantified their motility with a temporal resolution of 2 s. Using novel methods of analysis of growth cone dynamics, we show that transient activation of kainate receptors by bath-applied kainate induced a fast and reversible growth cone stalling. This effect depends on electrical activity and can be mimicked by the transient discharge of action potentials elicited in the neuron by intracellular current injections at the somatic level through a patch pipette. Growth cone stalling induced by electrical stimulation is mediated by calcium entry from the extracellular medium as well as by calcium release from intracellular stores that define spatially restricted microdomains directly affecting cytoskeletal dynamics. We propose that growth cone motility is dynamically controlled by transient bursts of spontaneous electrical activity, which constitutes a prominent feature of developing neural networksin vivo.
Early Sensory Pathways for Detection of Fearful Conditioned Stimuli: Tectal and Thalamic Relays
Authors: Cohen Jeremy D. , Castro-Alamancos Manuel A.
Published: July 2007

Sensory stimuli acquire significance through learning. A neutral sensory stimulus can become a fearful conditioned stimulus (CS) through conditioning. Here we report that the sensory pathways used to detect the CS depend on the conditioning paradigm. Animals trained to detect an electrical somatosensory stimulus delivered to the whisker pad in an active avoidance task were able to detect this CS and perform the task when a reversible or irreversible lesion was placed in either the somatosensory thalamus or the superior colliculus contralateral to the CS. However, simultaneous lesions of the somatosensory thalamus and superior colliculus contralateral to the CS blocked performance in the active avoidance task. In contrast, a lesion only of the somatosensory thalamus contralateral to the same CS, but not of the superior colliculus, blocked performance in a pavlovian fear conditioning task. In conclusion, during pavlovian fear conditioning, which is a situation in which the aversive outcome is not contingent on the behavior of the animal, the sensory thalamus is a critical relay for the detection of the CS. During active avoidance conditioning, a situation in which the aversive outcome is contingent on the behavior of the animal (i.e., the animal can avoid the aversive event), the sensory thalamus and the superior colliculus function as alternative routes for CS detection. Thus, even from early stages of sensory processing, the neural signals representing a CS are highly distributed in parallel and redundant sensory circuits, each of which can accomplish CS detection effectively depending on the conditioned behavior.
Experience-Dependent Increase in CA1 Place Cell Spatial Information, But Not Spatial Reproducibility, Is Dependent on the Autophosphorylation of the α-Isoform of the Calcium/Calmodulin-Dependent Protein Kinase II
Authors: Cacucci Francesca , Wills Thomas J. , Lever Colin , Giese Karl Peter , O'Keefe John
Published: July 2007

Place cells in hippocampal area CA1 are essential for spatial learning and memory. Here, we examine whether daily exposure to a previously unexplored environment can alter place cell properties. We demonstrate two previously unreported slowly developing plasticities in mouse place fields: both the spatial tuning and the trial-to-trial reproducibility of CA1 place fields improve over days. We asked whether these two components of improved spatial coding rely on the α-isoform of the calcium/calmodulin-dependent protein kinase II (αCaMKII) autophosphorylation, an effector mechanism of NMDA receptor-dependent long-term potentiation and an essential molecular process for spatial memory formation. We show that, in mice with deficient autophosphorylation of αCaMKII, the spatial tuning of place fields is initially similar to that of wild-type mice, but completely fails to show the experience-dependent increase over days. In contrast, place field reproducibility in the mutants, although impaired, does show the experience-dependent increase over days. Consequently, the progressive improvement in spatial coding in new hippocampal place cell maps depends on the existence of two molecularly dissociable, experience-dependent processes.
A microarray for microRNA profiling in mouse testis tissues
Authors: Yan Naihong , Lu Yilu , Sun Huaqin , Tao Dachang , Zhang Sizhong , Liu Wenying , Ma Yongxin
Published: July 2007

MicroRNAs (miRNAs) are short non-coding RNA molecules playing regulatory roles by repressing translation or cleaving RNA transcripts. Recent studies indicate that miRNAs are mechanistically involved in the development of mammalian spermatogenesis. However, little work has been done to compare the miRNA expression patterns between immature and mature mouse testes. Here, we employed a miRNA microarray to detect 892 miRNAs in order to evaluate the expression patterns of miRNA. The expression of 19 miRNAs was significantly different between immature and mature individuals. Fourteen miRNAs were significantly upregulated and five miRNAs were downregulated in immature mice and this result was further confirmed by a quantitative real-time RT-PCR assay. Many target genes involved in spermatogenesis are predicted by MiRscan performing miRNA target scanning. Our data indicated specific miRNAs expression in immature mouse testis and suggested that miRNAs have a role in regulating spermatogenesis.
Effects of cryopreservation on semen quality and the expression of sperm membrane hexose transporters in the spermatozoa of Iberian pigs
Authors: Sancho S , Casas I , Ekwall H , Saravia F , Rodriguez-Martinez H , Rodriguez-Gil J E , Flores E , Pinart E , Briz M , Garcia-Gil N , Bassols J , Pruneda A , Bussalleu E , Yeste M , Bonet S
Published: July 2007

This study evaluated the effects of cooling, freezing and thawing on the plasma membrane integrity, kinetics and expression of two sugar transporters glucose transporter-3 and -5 (GLUT-3 and GLUT-5) in spermatozoa from Iberian boars. Semen samples were collected twice weekly from eight young, fertile Iberian boars of the ‘Entrepelado’ and ‘Lampiño’ breeds. The samples were suspended in a commercial extender and refrigerated to 17 °C for transport to the laboratory (step A), where they were further extended with a lactose–egg yolk-based extender and chilled to 5 °C (step B) prior to freezing in the presence of glycerol (3%). Spermatozoa were assessed for plasma membrane integrity and sperm motility at each of the steps, including post-thaw (step C). Aliquots were also prepared for immunocytochemical localisation of the sugar transporters (fixed and thin smears for transmission and scanning electron microscopy levels respectively) and for SDS–PAGE electrophoresis and subsequent western blotting, using the same antibodies (rabbit anti-GLUT-3 and anti-GLUT-5 polyclonal antibodies). The results showed lower percentages of progressively motile spermatozoa at step C in both breeds, while the percentage of live spermatozoa was significantly lower only in the ‘Entrepelado’ breed. The results obtained from electron microscopy clearly showed that Iberian boar spermatozoa expressed the hexose transporters, GLUT-3 and GLUT-5. The pattern of expression, in terms of location and concentration, was characteristic in each case but, in the case of isoform GLUT-5, it remained constant during the different steps of freezing–thawing protocol. These results indicate that cryopreservation affects the status of sperm cells of Iberian boars by altering the distribution of some membrane receptors and decreasing the percentage values of parameters linked to sperm quality.
Intracerebroventricular administration of the prolactin (PRL) receptor antagonist, S179D PRL, disrupts parturition in rats
Authors: Nephew B C , Amico J , Cai H M , Walker A M , Bridges R S
Published: July 2007

The prolactin (PRL) receptor antagonist S179D PRL delays the onset of maternal behavior in steroid-primed nulliparous female rats. The present study investigated the role of the neural PRL system in the process of parturition. A preliminary study indicated that S179D PRL treatments administered by ALZET minipump to the lateral ventricle severely disrupted parturition. To examine the likely causes of this disruption, a group of timed-pregnant catheterized rats was continuously infused with S-179D PRL (0.001 and 0.1 ng/h) or vehicle control to the lateral ventricles for 3 days (gestation days 21–23), and serial blood samples were taken throughout this period. Effects of the treatments on parturition were recorded, and blood samples were assayed for PRL, progesterone, and oxytocin. Significantly fewer S179D PRL-treated rats successfully delivered by 1500 h on day 23 of gestation when compared with controls. The higher dose of S179D PRL also significantly suppressed the prepartum rise in PRL throughout the prepartum period, while the lower dose only affected plasma PRL during the first 24 h of treatment. No significant effects of the antagonist on plasma progesterone or oxytocin were detected. We conclude that disruption of parturition by S179D PRL is not caused by significant alterations in the plasma concentrations of progesterone or oxytocin. S179D PRL may indirectly act on parturition through the modulation of prepartum PRL. These findings suggest a previously unrecognized role for PRL in the regulation of parturition.
The Paleoproterozoic megascopic Stirling biota
Authors: Bengtson Stefan , Rasmussen Birger , Krapež Bryan
Published: July 2007

The 2.0–1.8-billion-year-old Stirling Range Formation in southwestern Australia preserves the deposits of a siliciclastic shoreline formed under the influence of storms, longshore currents, and tidal currents. Sandstones contain a megascopic fossil biota represented by discoidal fossils similar to the EdiacaranAspidellaBillings, 1872, as well as ridge pairs preserved in positive hyporelief on the soles of channel-fill sandstones bounded by mud drapes. The ridges run parallel or nearly parallel for most of their length, meeting in a closed loop at one end and opening with a slight divergence at the opposite end. The ridges are interpreted as casts of sediment-laden mucus strings formed by the movement of multicellular or syncytial organisms along a muddy surface. The taxaMyxomitodes stirlingensisn. igen., n. isp., are introduced for these traces. The Stirling biota was roughly coeval with other presumed multicellular eukaryotes appearing after a long period of profound environmental changes involving a rise in ambient oxygen levels, similar to that which preceded the Cambrian explosion. The failure of multicellular life to diversify during most of the Proterozoic may be due to environmental constraints related to the comparatively low level of oxidation of the world oceans.
BARNEGAT BAY–LITTLE EGG HARBOR ESTUARY: CASE STUDY OF A HIGHLY EUTROPHIC COASTAL BAY SYSTEM
Authors: Kennish Michael J. , Bricker Suzanne B. , Dennison William C. , Glibert Patricia M. , Livingston Robert J. , Moore Kenneth A. , Noble Rachel T. , Paerl Hans W. , Ramstack Joy M. , Seitzinger Sybil , Tomasko David A. , Valiela Ivan
Published: July 2007

The Barnegat Bay–Little Egg Harbor Estuary is classified here as a highly eutrophic estuary based on application of the National Oceanic and Atmospheric Administration's National Estuarine Eutrophication Assessment model. Because it is shallow, poorly flushed, and bordered by highly developed watershed areas, the estuary is particularly susceptible to the effects of nutrient loading. Most of this load (∼50%) is from surface water inflow, but substantial fractions also originate from atmospheric deposition (∼39%), and direct groundwater discharges (∼11%). No point source inputs of nutrients exist in the Barnegat Bay watershed. Since 1980, all treated wastewater from the Ocean County Utilities Authority's regional wastewater treatment system has been discharged 1.6 km offshore in the Atlantic Ocean. Eutrophy causes problems in this system, including excessive micro‐ and macroalgal growth, harmful algal blooms, altered benthic invertebrate communities, impacted harvestable fisheries, and loss of essential habitat (i.e., seagrass and shellfish beds). Similar problems are evident in other shallow lagoonal estuaries of the Mid‐Atlantic and South Atlantic regions. To effectively address nutrient enrichment problems in the Barnegat Bay–Little Egg Harbor Estuary, it is important to determine the nutrient loading levels that produce observable impacts in the system. It is also vital to continually monitor and assess priority indicators of water quality change and estuarine health. In addition, the application of a new generation of innovative models using web‐based tools (e.g., NLOAD) will enable researchers and decision‐makers to more successfully manage nutrient loads from the watershed. Finally, the implementation of storm water retrofit projects should have beneficial effects on the system.
PHYTOPLANKTON INDICATORS OF ECOLOGICAL CHANGE IN THE EUTROPHYING PAMLICO SOUND SYSTEM, NORTH CAROLINA
Authors: Paerl Hans W. , Valdes-Weaver Lexia M. , Joyner Alan R. , Winkelmann Valerie
Published: July 2007

Nutrient enrichment and eutrophication of estuarine and coastal waters are accelerating, and there is a need to develop rapidly detectable and quantifiable indicators of these changes. Coastal systems are also impacted by climatic perturbations, including droughts, storms, and floods, the frequencies of which may be increasing. Phytoplankton are excellent indicators of ecological change. They are relatively easy to detect, identify, and quantify; they conduct a large share of primary production; and they are sensitive to diverse environmental stressors. In this study, phytoplankton total biomass, as chlorophyll a, and group‐specific chemotaxonomic indicators (including chlorophylls and carotenoids) were used to characterize community responses to human (nutrient) and climatic (hydrologic) perturbations in the Neuse River Estuary–Pamlico Sound, North Carolina, USA. This estuarine–coastal continuum is experiencing anthropogenic nutrient enrichment and, since 1996, a rise in hurricane frequency. Freshwater input and flushing strongly interacted with supplies of the limiting nutrient nitrogen (N) to determine the location, magnitude, and composition of phytoplankton biomass along this continuum. Elevated flow (high flushing) following hurricanes favored dominance by the fast‐growing chlorophytes and cryptophytes. Diatoms tended to dominate under moderate flow, while dinoflagellates and cyanobacteria increased in dominance when low flow prevailed in winter/spring and summer/fall, respectively. Depending on seasonal hydrologic cycles and episodic (hurricane) conditions, phytoplankton community structure differed substantially. These changes impact eutrophication, food web, biogeochemical (e.g., hypoxia), and habitat conditions in this and other coastal ecosystems currently experiencing changes in nutrient inputs and climatic events. Phytoplankton‐based indicators are adaptable to unattended monitoring platforms (e.g., ferries) that can be coupled to remote sensing and modeling efforts, in order to evaluate and help manage ecological change at ecosystem and regional scales.
SUSCEPTIBILITY OF SALT MARSHES TO NUTRIENT ENRICHMENT AND PREDATOR REMOVAL
Authors: Deegan Linda A. , Bowen Jennifer L. , Drake Deanne , Fleeger John W. , Friedrichs Carl T. , Galván Kari A. , Hobbie John E. , Hopkinson Charles , Johnson D. Samuel , Johnson J. Michael , LeMay Lynsey E. , Miller Erin , Peterson Bruce J. , Picard Christian , Sheldon Sallie , Sutherland Michael , Vallino Joseph , Warren R. Scott
Published: July 2007

Salt marsh ecosystems have been considered not susceptible to nitrogen overloading because early studies suggested that salt marshes adsorbed excess nutrients in plant growth. However, the possible effect of nutrient loading on species composition, and the combined effects of nutrients and altered species composition on structure and function, was largely ignored. Failure to understand interactions between nutrient loading and species composition may lead to severe underestimates of the impacts of stresses. We altered whole salt marsh ecosystems (∼60 000 m2/treatment) by addition of nutrients in flooding waters and by reduction of a key predatory fish, the mummichog. We added nutrients (N and P; 15‐fold increase over ambient conditions) directly to the flooding tide to mimic the way anthropogenic nutrients are delivered to marsh ecosystems. Despite the high concentrations (70 mmol N/L) achieved in the water column, our annual N loadings (15–60 g N·m−2·yr−1) were an order of magnitude less than most plot‐level fertilization experiments, yet we detected responses at several trophic levels. Preliminary calculations suggest that 30–40% of the added N was removed by the marsh during each tidal cycle. Creek bank Spartina alterniflora and high marsh S. patens production increased, but not stunted high marsh S. alterniflora. Microbial production increased in the fertilized creek bank S. alterniflora habitat where benthic microalgae also increased. We found top‐down control of benthic microalgae by killifish, but only under nutrient addition and in the opposite direction (increase) than that predicted by a fish–invertebrate–microalgae trophic cascade. Surprisingly, infauna declined in abundance during the first season of fertilization and with fish removal. Our results demonstrate ecological effects of both nutrient addition and mummichog reduction at the whole‐system level, including evidence for synergistic interactions.