bluuebunny/crossref_metadata_2025 huggingface dataset:
The transport barrier in intraperitoneal therapy
Authors: Flessner Michael F.
Published: February 2005

The peritoneal cavity is important in clinical medicine because of its use as a portal of entry for drugs utilized in regional chemotherapy and as a means of dialysis for anephric patients. The barrier between the therapeutic solution in the cavity and the plasma does not correspond to the classic semipermeable membrane but instead is a complex structure of cells, extracellular matrix, and blood microvessels in the surrounding tissue. New research on the nature of the capillary barrier and on the orderly array of extracellular matrix molecules has provided insights into the physiological basis of osmosis and the alterations in transport that result from infusion of large volumes of fluid. The anatomic peritoneum is highly permeable to water, small solutes, and proteins and therefore is not a physical barrier. However, the cells of the mesothelium play an essential role in the immune response in the cavity and produce cytokines and chemokines in response to contact with noncompatible solutions. The process of inflammation, which depends on the interaction of mesothelial, interstitial, and endothelial cells, ultimately leads to angiogenesis and fibrosis and the functional alteration of the barrier. New animal models, such as the transgenic mouse, will accelerate the discovery of methods to preserve the functional peritoneal barrier.
Neural Sensitivity to Interaural Envelope Delays in the Inferior Colliculus of the Guinea Pig
Authors: Griffin Sarah J. , Bernstein Leslie R. , Ingham Neil J. , McAlpine David
Published: February 2005

Interaural time differences (ITDs) are important cues for mammalian sound localization. At high frequencies, sensitivity to ITDs, which are conveyed only by the envelope of the waveforms, has been shown to be poorer than sensitivity to ITDs at low frequencies, which are conveyed primarily by the fine structure of the waveforms. Recently, human psychophysical experiments have demonstrated that sensitivity to envelope-based ITDs in high-frequency transposed tones can be equivalent to low-frequency fine-structure–based ITD sensitivity. Transposed tones are designed to provide high-frequency auditory nerve fibers (ANFs) with similar temporal information to that provided by low-frequency tones. We investigated neural sensitivity to ITDs in high-frequency transposed and sinusoidally amplitude modulated (SAM) tones, in the inferior colliculus of the guinea pig. Neural sensitivity to ITDs in transposed tones was found to be greater than that to ITDs in SAM tones; in response to transposed tones, neural firing rates were more modulated as a function of ITD and discrimination thresholds were found to be lower than those in response to SAM tones. Similar to psychophysical findings, ITD discrimination of single neurons in response to transposed tones for rates of modulation <250 Hz was comparable to neural discrimination of ITDs in low-frequency tones. This suggests that the neural mechanisms that mediate sensitivity to ITDs at high and low frequencies are functionally equivalent, provided that the stimuli result in appropriate temporal patterns of action potentials in ANFs.
Neurodynamics of Biased Competition and Cooperation for Attention: A Model With Spiking Neurons
Authors: Deco Gustavo , Rolls Edmund T.
Published: February 2005

Recent neurophysiological experiments have led to a promising “ biased competition hypothesis” of the neural basis of attention. According to this hypothesis, attention appears as a sometimes nonlinear property that results from a top-down biasing effect that influences the competitive and cooperative interactions that work both within cortical areas and between cortical areas. In this paper we describe a detailed dynamical analysis of the synaptic and neuronal spiking mechanisms underlying biased competition. We perform a detailed analysis of the dynamical capabilities of the system by exploring the stationary attractors in the parameter space by a mean-field reduction consistent with the underlying synaptic and spiking dynamics. The nonstationary dynamical behavior, as measured in neuronal recording experiments, is studied by an integrate-and-fire model with realistic dynamics. This elucidates the role of cooperation and competition in the dynamics of biased competition and shows why feedback connections between cortical areas need optimally to be weaker by a factor of about 2.5 than the feedforward connections in an attentional network. We modeled the interaction between top-down attention and bottom-up stimulus contrast effects found neurophysiologically and showed that top-down attentional effects can be explained by external attention inputs biasing neurons to move to different parts of their nonlinear activation functions. Further, it is shown that, although NMDA nonlinear effects may be useful in attention, they are not necessary, with nonlinear effects (which may appear multiplicative) being produced in the way just described.
Variable Coupling Between Olfactory System Activity and Respiration in Ketamine/Xylazine Anesthetized Rats
Authors: Fontanini Alfredo , Bower James M.
Published: February 2005

In this study, we have characterized slow and fast oscillations at several stages of olfactory processing under light and deep ketamine/xylazine anesthesia in the albino rat. While monitoring the animal's respiration, we also obtained field potentials from the olfactory bulb and piriform (olfactory) cortex and simultaneously recorded membrane potentials in piriform cortex pyramidal cells. Our results demonstrate that oscillations are generally found at higher frequencies under lighter and lower frequencies under deeper anesthesia. In previous studies of cerebral cortex, similar results in ketamine/xylazine anesthetized animals have been interpreted to correspond with the higher frequencies found during waking and lower frequencies found in the sleep state. Correlation and coherence analysis between data obtained in the bulb and cortex reveals a clear difference in coupling depending on the anesthetic state of the animal. Specifically, activity recorded in the whole system is highly correlated with respiration during deep anesthesia, whereas only the olfactory bulb, and not the cortex, is correlated with respiration during light anesthesia. These data suggest that global activity in the piriform cortex is actually more directly tied to peripheral slow respiratory input during slow wave than fast wave states and that the coupling between olfactory structures can be dynamically modulated by the level of anesthesia and therefore presumably by different brain states as well.
Changes in ADAMTS13 (von-Willebrand-factor-cleaving protease) activity after induced release of von Willebrand factor during acute systemic inflammation
Authors: Reiter Rosemarie , Varadi Katalin , Turecek Peter , Knöbl Paul , Jilma Bernd
Published: February 2005

Von Willebrand factor (VWF) is synthesized in endothelial cells, stored in the form of high molecular weight multimers and released after stimulation. After release, the multimers are cleaved by ADAMTS13 (von-Willebrand-factor-cleaving protease). We studied healthy volunteers in a double-blind, placebo controlled inflammation model. Ten male volunteers received 2 ng/kg endotoxin intravenously, and 5 volunteers placebo. Endotoxin infusion induced systemic inflammation and coagulation activation. After 4 hours the observed increase in neutrophils reached a maximum (273±34 % of baseline; mean ± SEM) and the platelet count dropped (81±2 %). These parameters returned to baseline values after 24 hours. VWF antigen increased to 259±16 % of baseline after 4 hours, remained elevated (192±15 %) after 24 hours and returned to baseline after 7 days. Unusually large VWF multimers occurred in the plasma 4 hours after endotoxin infusion. ADAMTS13 activity (measured with a collagen-binding assay) decreased to 64±5 % of baseline (P< 0.001) after 4 hours, was still reduced after 24 hours (86±6 %; P=0.008) and returned to normal after 7 days. VWF multimer analysis showed pronounced satellite bands in the 4-hour samples, indicating cleavage of VWF by ADAMTS13. No apparent changes of the analyzed parameters were observed in the placebo group. The reciprocal course of ADAMTS13 and VWF after short-term VWF release induced by systemic inflammation is similar to that observed after induction of VWF release by desmopressin.
Gene duplication of coagulation factor V and origin of venom prothrombin activator in Pseudonaja textilis snake
Authors: Minh Le Thi Nguyet , Reza Md Abu , Swarup Sanjay , Kini R. Manjunatha
Published: February 2005

The origin and evolution of venom toxins is a mystery that has evoked much interest. We have recently shown that pseutarin C, a prothrombin activator from Pseudonaja textilis venom, is structurally and functionally similar to mammalian coagulation factor Xa – factor Va complex. Its catalytic subunit is homologous to factor Xa while the nonenzymatic subunit is homologous to factor Va. P.textilis therefore has two parallel prothrombin activator systems: one expressed in its venom gland as a toxin and the other expressed in its liver and released into its plasma as a haemostatic factor. Here we report the complete amino acid sequence of factor V (FV) from its liver determined by cDNA cloning and sequencing. The liver FV shows 96% identity to pseutarin C nonenzymatic subunit. Most of the functional sites involved in its interaction with factor Xa and prothrombin are conserved. However, many potential sites of post-translational modifications and one critical cleavage site for activated protein C are different. The absence of the latter cleavage site makes pseutarin C nonenzymatic subunit resistant to inactivation and enhances its potential as an excellent toxin. By PCR and real-time quantitative analysis, we show that pseutarin C nonenzymatic subunit gene is expressed specifically in the venom gland at ~280 fold higher than that of FV gene in liver. These two are thus encoded by two separate genes that express in a highly tissue-specific manner. Our results imply that the gene encoding pseutarin C nonenzymatic subunit was derived by the duplication of plasma FV gene and they have evolved to perform distinct functions.
Protein Z and protein Z-dependent protease inhibitor
Authors: Al-Shanqeeti Ali , van Hylckama Vlieg Astrid , Berntorp Erik , Rosendaal Frits , Broze George
Published: February 2005

To assess the potential roles of protein Z (PZ) and protein Z-dependent protease inhibitor (ZPI) in venous thrombosis, their plasma levels were measured in 426 individuals with venous thrombosis and 471 control individuals participating in the Leiden Thrombophilia Study. A relationship between the level of PZ or ZPI and venous thrombosis was not detected in the overall case-control study. PZ and ZPI circulate as a complex and their plasma levels are interdependent. Both PZ and ZPI are increased with oral contraceptive use and reduced with oral anticoagulant therapy.
Transient Receptor Potential Melastatin 7 Ion Channels Regulate Magnesium Homeostasis in Vascular Smooth Muscle Cells
Authors: He Ying , Yao Guoying , Savoia Carmine , Touyz Rhian M.
Published: February 2005

Magnesium modulates vascular smooth muscle cell (VSMC) function. However, molecular mechanisms regulating VSMC Mg
2+
remain unknown. Using biochemical, pharmacological, and genetic tools, the role of transient receptor potential membrane melastatin 7 (TRPM7) cation channel in VSMC Mg
2+
homeostasis was evaluated. Rat, mouse, and human VSMCs were studied. Reverse transcriptase polymerase chain reaction and immunoblotting demonstrated TRPM7 presence in VSMCs (membrane and cytosol). Angiotensin II (Ang II) and aldosterone increased TRPM7 expression. Gene silencing using small interfering RNA (siRNA) against TRPM7, downregulated TRPM7 (mRNA and protein). Basal [Mg
2+
]
i
, measured by mag fura-2AM, was reduced in siRNA-transfected cells (0.39±0.01 mmol/L) versus controls (0.54±0.01 mmol/L;
P
<0.01). Extracellular Mg
2+
dose-dependently increased [Mg
2+
]
i
in control cells (E
max
0.70±0.02 mmol/L) and nonsilencing siRNA-transfected cells (E
max
0.71±0.04 mmol/L), but not in siRNA-transfected cells (E
max
0.5±0.01 mmol/L). The functional significance of TRPM7 was evaluated by assessing [Mg
2+
]
i
and growth responses to Ang II in TRPM7 knockdown cells. Acute Ang II stimulation decreased [Mg
2+
]
i
in control and TRPM7-deficient cells in a Na
+
-dependent manner. Chronic stimulation increased [Mg
2+
]
i
in control, but not in siRNA-transfected VSMCs. Ang II–induced DNA and protein synthesis, measured by
3
[H]-thymidine and
3
[H]-leucine incorporation, respectively, were increased in control and nonsilencing cells, but not in TRPM7 knockdown VSMCs. Our data indicate that VSMCs possess membrane-associated, Ang II–, and aldosterone-regulated TRPM7 channels, which play a role in regulating basal [Mg
2+
]
i
, transmembrane Mg
2+
transport and DNA and protein synthesis. These novel findings identify TRPM7 as a functionally important regulator of Mg
2+
homeostasis and growth in VSMCs.
Subhas Chandra Bose, Japan and British Imperialism
Authors:   Sareen
Published: February 2005

This paper examines the strategic framework of action of Subhas Chandra Bose for the liberation of India and how his ideas about international collaboration for the overthrow of British imperialism took shape despite the constraints and limitations imposed by the existing framework of the national moment as conceived by Gandhi and the restrictions imposed by the colonial rulers. An attempt is made in this paper to analyse how his collaboration with Japan directly or indirectly accelerated the pace of nationalism during and after the Second World War.
Refurbishing Hong Kong's Image: The 1997 Saga and Chinese Nationalism Under Deng Xiaoping
Authors: Kwong Luke
Published: February 2005

This article argues that the People's Republic of China used Hong Kong's reversion in 1997, a reluctant project at first, as an opportunity to articulate its national aspirations in the post-Mao era. Of special interest is the shift of the Chinese view of Hong Kong from one of ideological degradation to one of kinder, gentler and more contextualized appreciation. Chinese attempts to refashion Hong Kong's image in the 1980s and 1990s attested to two salient features of Deng Xiaoping's reform regime: the decline of Marxist ideology and the resurgence of nationalism.
How Thales Was Able to "Predict" a Solar Eclipse Without the Help of Alleged Mesopotamian Wisdom
Authors: Couprie Dirk
Published: February 2005

The first part of this article examines Patricia O'Grady's recent attempt to identify the method by which Thales might have successfully predicted a solar eclipse. According to O'Grady, some 60% of the potentially visible lunar eclipses were followed 23½ months later by potentially visible solar eclipses. It is shown that this ratio is no more than 23%, and that the method fails to predict after which specific lunar eclipse a solar eclipse will appear. In the second half of the article it is argued that on the basis of his own observations of major solar eclipses, Thales could have concluded that solar eclipses come in clusters of three, the second appearing 17 or 18 months, and the third 35 months, after the first one. In the years after the "predicted" eclipse of 28 May 585 BC, this apparent pattern disappeared again, which would explain why Thales managed to "predict" only one eclipse.
Appreciative Inquiry in Building a Transcultural Strategic Alliance
Authors: Miller Monty G. , Fitzgerald Stephen P. , Murrell Kenneth L. , Preston Joanne , Ambekar Rajendra
Published: February 2005

Building relationships and developing understanding, trust, and collaboration in transcultural strategic alliances involve enormous challenges that have been well documented. Organization development (OD) technologies, including appreciative inquiry (AI), are uniquely suited to deal effectively with these challenges. Thus, two alliancebuilding OD interventions were implemented to develop relational capital in a U.S.-India biotechnology alliance. Substantive cultural differences existed between the alliance partners at formation, and the ways in which those differences influenced the design and implementation of the two interventions are discussed. Overall, AI as modified was found to support building relational capital. Six years later, the alliance continues to thrive; however, many of the same issues that hampered the effectiveness of collaboration and building of trust in the alliance still exist. Recommendations are offered for modifying the design of AI and other OD interventions to provide ongoing support for building successful transcultural alliances.
Toward a Patient-Centered Approach: Incorporating Principles of Participatory Action Research Into Clinical Studies
Authors: White Margaret A. , Verhoef Marja J.
Published: February 2005

Despite the shift to patient-centered care in recent years, many clinical studies continue to reinforce the traditional researcher/subject relationship. In contrast, action research engages study participants in a collaborative relationship with researchers. Objectives: To review the benefits of adding a participatory component to an existing study with respect to (1) engaging participants in the research process to clarify and validate qualitative findings, (2) engaging participants in the change process to develop potential solutions for improving integrative cancer services, and (3) giving voice to the concerns of patients using complementary and alternative medicine. Method: Focus groups were used to clarify concepts arising from patient interviews and to provide a forumfor participants to develop recommendations and facilitate dissemination. Conclusion: Our approach empowered patients by involving them in the research and in developing solutions for how health care providers, policy makers, and researchers can enhance an integrative approach to cancer care.
The Severe Acute Respiratory Syndrome (SARS)-coronavirus 3a protein may function as a modulator of the trafficking properties of the spike protein
Authors: Tan Yee-Joo
Published: February 2005

Background

A recent publication reported that a tyrosine-dependent sorting signal, present in cytoplasmic tail of the spike protein of most coronaviruses, mediates the intracellular retention of the spike protein. This motif is missing from the spike protein of the severe acute respiratory syndrome-coronavirus (SARS-CoV), resulting in high level of surface expression of the spike protein when it is expressed on its own in vitro.

Presentation of the hypothesis

It has been shown that the severe acute respiratory syndrome-coronavirus genome contains open reading frames that encode for proteins with no homologue in other coronaviruses. One of them is the 3a protein, which is expressed during infection in vitro and in vivo. The 3a protein, which contains a tyrosine-dependent sorting signal in its cytoplasmic domain, is expressed on the cell surface and can undergo internalization. In addition, 3a can bind to the spike protein and through this interaction, it may be able to cause the spike protein to become internalized, resulting in a decrease in its surface expression.

Testing the hypothesis

The effects of 3a on the internalization of cell surface spike protein can be examined biochemically and the significance of the interplay between these two viral proteins during viral infection can be studied using reverse genetics methodology.

Implication of the hypothesis

If this hypothesis is proven, it will indicate that the severe acute respiratory syndrome-coronavirus modulates the surface expression of the spike protein via a different mechanism from other coronaviruses. The interaction between 3a and S, which are expressed from separate subgenomic RNA, would be important for controlling the trafficking properties of S. The cell surface expression of S in infected cells significantly impacts viral assembly, viral spread and viral pathogenesis. Modulation by this unique pathway could confer certain advantages during the replication of the severe acute respiratory syndrome-coronavirus.
Mesenchymal progenitor cells localize within hematopoietic sites throughout ontogeny
Authors: Mendes Sandra C. , Robin Catherine , Dzierzak Elaine
Published: February 2005

Mesenchymal stem cells (MSCs) have great clinical potential for the replacement and regeneration of diseased or damaged tissue. They are especially important in the production of the hematopoietic microenvironment,which regulates the maintenance and differentiation of hematopoietic stem cells (HSCs). In the adult, MSCs and their differentiating progeny are found predominantly in the bone marrow (BM). However, it is as yet unknown in which embryonic tissues MSCs reside and whether there is a localized association of these cells within hematopoietic sites during development. To investigate the embryonic origins of these cells, we performed anatomical mapping and frequency analysis of mesenchymal progenitors at several stages of mouse ontogeny. We report here the presence of mesenchymal progenitors, with the potential to differentiate into cells of the osteogenic, adipogenic and chondrogenic lineages, in most of the sites harboring hematopoietic cells. They first appear in the aorta-gonad-mesonephros (AGM) region at the time of HSC emergence. However, at this developmental stage, their presence is independent of HSC activity. They increase numerically during development to a plateau level found in adult BM. Additionally, mesenchymal progenitors are found in the embryonic circulation. Taken together, these data show a co-localization of mesenchymal progenitor/stem cells to the major hematopoietic territories, suggesting that, as development proceeds,mesenchymal progenitors expand within these potent hematopoietic sites.
Characterization of Nfatc1 regulation identifies an enhancer required for gene expression that is specific to pro-valve endocardial cells in the developing heart
Authors: Zhou Bin , Wu Bingruo , Tompkins Kevin L. , Boyer Kathleen L. , Grindley Justin C. , Baldwin H. Scott
Published: February 2005

Nfatc1 is an endocardial transcription factor required for development of cardiac valves. Herein, we describe identification and characterization of a tissue-specific enhancer in the first intron of murine Nfatc1 that activates a heterogenic promoter and directs gene expression in a subpopulation of endocardial cells of the developing heart: the pro-valve endocardial cells. This enhancer activity begins on embryonic day (E) 8.5 in endocardial cells at the ventricular end of the atrioventricular canal,intensifies and extends from E9.5 to E11.5 in endocardium along the atrioventricular canal and outflow tract. By E12.5, the enhancer activity is accentuated in endocardial cells of forming valves. Sequential deletion analysis identified that a 250 bp DNA fragment at the 3′ end of the intron 1 is required for endocardial-specific activity. This region contains two short conserved sequences hosting a cluster of binding sites for transcription factors, including Nfat and Hox proteins. Electrophoresis mobility shift and chromatin immunoprecipitation assays demonstrated binding of Nfatc1 to the Nfat sites, and inactivation of Nfatc1 downregulated the enhancer activity in pro-valve endocardial cells. By contrast, mutation of the Hox site abolished its specificity, allowing gene expression in non pro-valve endocardium and extracardiac vasculature. Thus, autoregulation of Nfatc1 is required for maintaining high Nfatc1 expression in pro-valve endocardial cells, while suppression through the Hox site prevents its expression outside pro-valve endocardial cells during valve development. Our data demonstrate the first autonomous cell-specific enhancer for pro-valve endocardial cells and delineate a unique transcriptional mechanism that regulates endocardial Nfatc1 expression within developing cardiac valves.
ULTRAPETALA1encodes a SAND domain putative transcriptional regulator that controls shoot and floral meristem activity inArabidopsis
Authors: Carles Cristel C. , Choffnes-Inada Dan , Reville Keira , Lertpiriyapong Kvin , Fletcher Jennifer C.
Published: February 2005

The higher-plant shoot apical meristem is a dynamic structure continuously producing cells that become incorporated into new leaves, stems and flowers. The maintenance of a constant flow of cells through the meristem depends on coordination of two antagonistic processes: self-renewal of the stem cell population and initiation of the lateral organs. This coordination is stringently controlled by gene networks that contain both positive and negative components. We have previously defined the ULTRAPETALA1(ULT1) gene as a key negative regulator of cell accumulation in Arabidopsis shoot and floral meristems, because mutations in ULT1 cause the enlargement of inflorescence and floral meristems, the production of supernumerary flowers and floral organs, and a delay in floral meristem termination. Here, we show that ULT1 negatively regulates the size of the WUSCHEL (WUS)-expressing organizing center in inflorescence meristems. We have cloned the ULT1 gene and find that it encodes a small protein containing a B-box-like motif and a SAND domain, a DNA-binding motif previously reported only in animal transcription factors. ULT1 and its Arabidopsis paralog ULT2 define a novel small gene family in plants. ULT1 and ULT2 are expressed coordinately in embryonic shoot apical meristems, in inflorescence and floral meristems, and in developing stamens, carpels and ovules. Additionally, ULT1 is expressed in vegetative meristems and leaf primordia. ULT2 protein can compensate for mutant ULT1 protein when overexpressed in an ult1 background, indicating that the two genes may regulate a common set of targets during plant development. Downregulation of both ULT genes can lead to shoot apical meristem arrest shortly after germination, revealing a requirement for ULT activity in early development.
Delta-Notch signalling controls commitment to a secretory fate in the zebrafish intestine
Authors: Crosnier Cécile , Vargesson Neil , Gschmeissner Stephen , Ariza-McNaughton Linda , Morrison Alastair , Lewis Julian
Published: February 2005

The transparency of the juvenile zebrafish and its genetic advantages make it an attractive model for study of cell turnover in the gut. BrdU labelling shows that the gut epithelium is renewed in essentially the same way as in mammals: the villi are lined with non-dividing differentiated cells, while cell division is confined to the intervillus pockets. New cells produced in the pockets take about 4 days to migrate out to the tips of the villi, where they die. We have generated monoclonal antibodies to identify the absorptive and secretory cells in the epithelium, and we have used these antibodies to examine the part that Delta-Notch signalling plays in producing the diversity of intestinal cell types. Several Notch receptors and ligands are expressed in the gut. In particular, the Notch ligand DeltaD (Delta1 in the mouse) is expressed in cells of the secretory lineage. In an aei mutant, where DeltaD is defective, secretory cells are overproduced. In mind bomb(mib), where all Delta-Notch signalling is believed to be blocked,almost all the cells in the 3-day gut epithelium adopt a secretory character. Thus, secretory differentiation appears to be the default in the absence of Notch activation, and lateral inhibition mediated by Delta-Notch signalling is required to generate a balanced mixture of absorptive and secretory cells. These findings demonstrate the central role of Notch signalling in the gut stem-cell system and establish the zebrafish as a model for study of the mechanisms controlling renewal of gut epithelium.
aPKC, Crumbs3 and Lgl2 control apicobasal polarity in early vertebrate development
Authors: Chalmers Andrew D. , Pambos Michael , Mason Julia , Lang Stephanie , Wylie Chris , Papalopulu Nancy
Published: February 2005

In early vertebrate development, apicobasally polarised blastomeres divide to produce inner non-polarised cells and outer polarised cells that follow different fates. How the polarity of these early blastomeres is established is not known. We have examined the role of Crumbs3, Lgl2 and the apical aPKC in the polarisation of frog blastomeres. Lgl2 localises to the basolateral membrane of blastomeres, while Crumbs3 localises to the apical and basolateral membranes. Overexpression aPKC and Crumbs3 expands the apical domain at the expense of the basolateral and repositions tight junctions in the new apical-basolateral interface. Loss of aPKC function causes loss of apical markers and redirects basolateral markers ectopically to the apical membrane. Cell polarity and tight junctions, but not cell adhesion,are lost and outer polarised cells become inner-like apolar cells. Overexpression of Xenopus Lgl2 phenocopies the aPKCknockout, suggesting that Lgl2 and aPKC act antagonistically. This was confirmed by showing that aPKC and Lgl2 can inhibit the localisation of each other and that Lgl2 rescues the apicalisation caused by aPKC. We conclude that an instrumental antagonistic interaction between aPKC and Lgl2 defines apicobasal polarity in early vertebrate development.
RhoGEF2 and the formin Dia control the formation of the furrow canal by directed actin assembly duringDrosophilacellularisation
Authors: Großhans Jörg , Wenzl Christian , Herz Hans-Martin , Bartoszewski Slawomir , Schnorrer Frank , Vogt Nina , Schwarz Heinz , Müller H.-Arno
Published: February 2005

The physical interaction of the plasma membrane with the associated cortical cytoskeleton is important in many morphogenetic processes during development. At the end of the syncytial blastoderm of Drosophila the plasma membrane begins to fold in and forms the furrow canals in a regular hexagonal pattern. Every furrow canal leads the invagination of membrane between adjacent nuclei. Concomitantly with furrow canal formation, actin filaments are assembled at the furrow canal. It is not known how the regular pattern of membrane invagination and the morphology of the furrow canal is determined and whether actin filaments are important for furrow canal formation. We show that both the guanyl-nucleotide exchange factor RhoGEF2 and the formin Diaphanous (Dia) are required for furrow canal formation. In embryos from RhoGEF2 or dia germline clones, furrow canals do not form at all or are considerably enlarged and contain cytoplasmic blebs. Both Dia and RhoGEF2 proteins are localised at the invagination site prior to formation of the furrow canal. Whereas they localise independently of F-actin,Dia localisation requires RhoGEF2. The amount of F-actin at the furrow canal is reduced in dia and RhoGEF2 mutants,suggesting that RhoGEF2 and Dia are necessary for the correct assembly of actin filaments at the forming furrow canal. Biochemical analysis shows that Rho1 interacts with both RhoGEF2 and Dia, and that Dia nucleates actin filaments. Our results support a model in which RhoGEF2 and dia control position, shape and stability of the forming furrow canal by spatially restricted assembly of actin filaments required for the proper infolding of the plasma membrane.
Identification of Serum Amyloid A as a Biomarker to Distinguish Prostate Cancer Patients with Bone Lesions
Authors: Le Lyly , Chi Kim , Tyldesley Scott , Flibotte Stephane , Diamond Deborah L , Kuzyk Michael A , Sadar Marianne D
Published: February 2005

Background: Prostate cancer has a propensity to metastasize to the bone. Currently, there are no curative treatments for this stage of the disease. Sensitive biomarkers that can be monitored in the blood to indicate the presence or development of bone metastases and/or response to therapies are lacking. Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) is an affinity-based approach that allows sensitive and high-throughput protein profiling and screening of biological samples.

Methods: We used SELDI-TOF MS for protein profiling of sera from prostate cancer patients (n = 38) with and without bone metastases in our effort to identify individual or multiple serum markers that may be of added benefit to those in current use. Serum was applied to ProteinChip® surfaces (H4 and IMAC) to quickly screen samples and detect peaks predominating in the samples obtained from patients with bone metastases. Unique proteins in the bone metastasis cohort observed by SELDI-TOF MS were identified by two-dimensional gel electrophoresis, in-gel trypsin digestion, and tandem MS. The identities of the proteins were confirmed by ELISA and immunodepletion assays.

Results: The cluster of unique proteins in the sera of patients with bone metastases was identified as isoforms of serum amyloid A. Machine-learning algorithms were also used to identify patients with bone metastases with a sensitivity and specificity of 89.5%.

Conclusions: SELDI-TOF MS protein profiling in combination with other proteomic approaches may provide diagnostic tools with potential clinical applications and serve as tools to aid in the discovery of biomarkers associated with various diseases.
Biological activity of activating thyrotrophin receptor mutants: modulation by iodide
Authors: Al-Khafaji F , Wiltshire M , Fuhrer D , Mazziotti G , Lewis M D , Smith P J , Ludgate M
Published: February 2005

Epidemiological studies have revealed a significantly higher incidence of toxic adenoma (TA) and toxic multi-nodular goitre (TMNG) in regions of iodine deficiency. Fifty to eighty percent of TA and TMNG are caused by activation of the cAMP pathway, mostly by mutations in the thyrotrophin receptor (TSHR).

We aimed to investigate whether iodide could modulate the biological effects of activating TSHR mutations. We have applied an in vitro model of TA comprising FRTL-5 cells stably expressing activating TSHR. We have mimicked the in vivo situation by examining the effects of prolonged exposure to iodide on the proliferation and signal transduction etc. of these cells.

We observed an iodide-induced ‘inhibition of proliferation’ which was significant from 10 mM in the presence of serum but from 1 mM in its absence. The inhibition of proliferation was significantly higher in the activating mutant expressing FRTL-5 compared with control Neo or wild-type TSHR, indicating that the effect was mediated via the cAMP cascade. The effect was neither due to hyper-tonicity nor was it the result of an increase in cell death either by apoptosis or necrosis. Prolonged exposure to iodide produces an increase in cells in the G2 and post-G2 phases, indicating that G2/M blockade contributes to the mechanism of inhibition.

The mutant expressing FRTL-5 cells have increased proliferation when chronically exposed to TSH, and this is associated with a reduction in phosphorylated (p) CREB levels. This contrasts with the effect of iodide in which inhibition of proliferation is accompanied by an increase in pCREB.

In conclusion, our studies indicate that the biological effects of activating TSHR mutations vary with the ambient iodide supply and could be masked in regions of high iodine intake.
Differential effects of 16α-hydroxyestrone and 2-methoxyestradiol on cyclin D1 involving the transcription factor ATF-2 in MCF-7 breast cancer cells
Authors: Lewis Joan S , Thomas T J , Pestell Richard G , Albanese Chris , Gallo Michael A , Thomas Thresia
Published: February 2005

We studied the effects of 2-methoxyestradiol (2-ME2) and 16α-hydroxyestrone (16α-OHE1), two metabolites of estradiol (E2), on DNA synthesis, cell cycle progression and cyclin D1 protein levels in estrogen receptor-positive MCF-7 cells. E2 and 16α-OHE1 stimulated DNA synthesis, and 2-ME2 inhibited the stimulatory effects of these agents. E2 and 16α-OHE1 stimulated the progression of cells from G1 to S phase and this effect was attenuated by 2-ME2. Western blot analysis showed that E2 and 16α-OHE1 increased cyclin D1 protein level by about fourfold compared with control. 2-ME2 had no significant effect on cyclin D1; however, it prevented the accumulation of cyclin D1 in the presence of E2 and 16α-OHE1. Cells transfected with a cyclin D1 reporter gene and treated with E2 or 16α-OHE1 showed 7- and 9.5-fold increase respectively in promoter activity compared with control. This activity was significantly inhibited by 2-ME2. Cyclin D1 transactivation was mediated by the cAMP response element (CRE) region, which binds activating transcription factor 2 (ATF-2). DNA affinity assay showed 2.5- and 3.5-fold increases in ATF-2 binding to CRE in the presence of E2 and 16α-OHE1 respectively. The binding of ATF-2 was inhibited by the presence of 2-ME2. These results show that 2-ME2 can downregulate cyclin D1 and thereby cell cycle progression by a mechanism involving the disruption of ATF-2 binding to cyclin D1 promoter.
Identification of human myometrial target genes of the c-Jun NH2-terminal kinase (JNK) pathway: the role of activating transcription factor 2 (ATF2) and a novel spliced isoform ATF2-small
Authors: Bailey Jarrod , Europe-Finner G Nicholas
Published: February 2005

Activating transcription factor 2 (ATF2), a ubiquitously expressed member of the basic region leucine zipper (bZIP) family of transcription factors activated by mitogen activated protein kinase (MAPK) pathways, is important in the mediation of cellular stress responses, development and transformation. We have previously reported the differential expression of active ATF2 in the human myometrium throughout pregnancy and labour, and identified and partially characterized a novel splice variant ATF2-small (ATF2-sm). To further understand the role of these factors in the myometrium, we have used gene microarrays to define the target genes in cultured myometrial cells stably-transfected with ATF2 and ATF2-sm cDNAs. Many of the genes identified appear to have potential roles in regulating myometrial function and include proteins involved in G-protein receptor signalling, cytokine signalling, transcriptional regulation, cell-cycle control, formation of the extracellular matrix and cytoskeletal architecture. ATF2 was found to affect the expression of 204 genes; 113 being up-regulated and 91 down-regulated whereas the novel ATF2-sm factor altered the expression of 55 genes; expression was increased in 29 cases and decreased in 26. A further 25 genes affected by ATF2-sm were identified by suppression subtractive hybridisation (SSH). Notably, the genes affected by ATF2 and ATF2-sm appear to belong to discrete groups: only two genes were affected by both factors.
Photoelectron Spectra and Electronic Structures of Substituted Pyrimidines
Authors: Lottermoser Ursula , Rademacher Paul , Mazik Monika , Kowski Klaus
Published: February 2005

The electronic structures of pyrimidine (1) and its substituted derivatives 2−15 have been investigated by ultraviolet photoelectron spectroscopy and quantum chemical methods. The ionisation potentials corresponding to the π MOs π1‐π3 and the two nN orbitals of the pyrimidine unit could be determined and assigned for 1−15. Multiple linear regression analyses of the IPs related to these orbitals with different substituent constants indicated that Hammett σp values performed well for all these IPs, whereas the resonance parameters R and R+ were satisfactory for π and poor for nN ionisations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Agaricus macrosporus as a potential bioremediation agent for substrates contaminated with heavy metals
Authors: García MA , Alonso J , Melgar MJ
Published: February 2005

This study investigated the potential use of the mushroom Agaricus macrosporus for bioextraction of heavy metals from contaminated substrates. Mushrooms were grown (1) in a non‐contaminated control substrate, (2) in a substrate with added Cd (10 mg per kg dw), and (3) in a multi‐contaminated substrate (Cd, Hg and Pb each at 10 mg kg−1; Cu and Zn each at 20 mg kg−1). Metal contents were determined in fruiting bodies by anodic stripping voltammetry (ASV). In the control substrate, three production waves (‘breaks’) were obtained, compared with only two in the contaminated substrates; however, total biomass in the Cd‐contaminated substrate was similar to that in the control substrate, and only 40% lower (ie still considerable) in the Hg‐containing multi‐contaminated substrate. Within each break, metal contents were higher in young than in adult individuals. Metal contents were also higher in the hymenophore than in other parts of the fruiting body. The metal content data indicate that A macrosporus effectively extracted Cd, Hg and Cu (though not Pb) from the contaminated substrates. Of particular interest is the tolerance and extraction of Hg, in contrast with plants. These results suggest that fungi such as A macrosporus may be effective for bioremediation of metal‐contaminated substrates, though bearing in mind that in many contaminated environments cultivation of mushrooms of this type may be difficult. Copyright © 2005 Society of Chemical Industry
(Plasticized) Polylactide/(Organo‐)Clay Nanocomposites by in situ Intercalative Polymerization
Authors: Paul Marie‐Amélie , Delcourt Cécile , Alexandre Michaël , Degée Philippe , Monteverde Fabien , Rulmont André , Dubois Philippe
Published: February 2005

Summary: Both intercalated and exfoliated poly(L,L‐lactide) (P(L,L‐LA)/organomodified montmorillonite nanocomposites were synthesized by in situ ring‐opening polymerization of L,L‐lactide, in bulk, directly in the presence of the nanofiller. Intercalation of polyester chains was found to appear even for natural unmodified montmorillonite‐Na+, while exfoliation occurred when the aluminosilicate layers were modified by ammonium cations bearing primary hydroxyl groups. Clay delamination was effectively triggered by the grafting reaction of the growing PLA chains onto the hydroxyl groups. Aluminium triisopropoxide, triethylaluminium, and stannous octoate, as initiating or co‐initiating species, were compared in terms of polymerization control. The influence of nanoclay content (from 1 to 10 wt.‐% in inorganics) on morphology and thermal behavior was also studied. In parallel, a highly filled nanocomposite (called masterbatch), prepared by in situ polymerization, was dispersed into a (plasticized) preformed polylactide matrix in the molten state, to reach a better clay delamination than that obtained by direct melt blending. Finally, L,L‐lactide and α,ω‐dihydroxylated poly(ethylene glycol) (PEG 1000) were copolymerized in presence of clay in order to study the behavior of the resulting triblocks towards nanocomposite formation.

Significant exfoliation of clay platelets has been achieved in a commercial polylactide matrix using a “masterbatch” process (white arrows).

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Significant exfoliation of clay platelets has been achieved in a commercial polylactide matrix using a “masterbatch” process (white arrows).
Novel Phosphorous‐Containing Aromatic Polyethers – Synthesis and Characterization
Authors: Hoffmann Thorsten , Pospiech Doris , Häußler Liane , Komber Hartmut , Voigt Dieter , Harnisch Christina , Kollann Carsten , Ciesielski Michael , Döring Manfred , Perez‐Graterol Raul , Sandler Jan , Altstädt Volker
Published: February 2005

Summary: The synthesis of novel phosphorous‐containing aromatic polyethers P‐PEEK and P‐PSU, based on poly(ether ether ketone)s (PEEK) and poly(ether sulfone)s (PSU) was carried out successfully by using phosphorous‐containing aromatic diols instead of bisphenol A in the usual synthesis procedure. The molecular weights of the P‐PEEKs and P‐PSUs obtained reflect both the influence of the different halogen components used and the lower thermal stabilities of the phosphorous‐containing diols compared to bisphenol A. However, polymers with sufficient molecular weights could be obtained, having interestingly high Tgs, high thermal stabilities as well as modified flame retardance properties depending on the diol type incorporated.

Comparison of the molecular weights of the synthesized P‐polyethers.

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Comparison of the molecular weights of the synthesized P‐polyethers.
End‐Anchored Polymers: Compression by Different Mechanisms and Interpenetration of Apposing Layers
Authors: Whitmore Mark D. , Baranowski Roman
Published: February 2005

Summary: This paper presents a systematic study of the compression of end‐anchored polymer layers by a variety of mechanisms. We treat layers in both good and Θ solvents, and in the range of polymer densities that is normally encountered in experiments. Our primary technique is numerical self‐consistent field (NSCF) theory. We compare the NSCF results for the different mechanisms with each other, and with those of the analytic SCF theory. For each mechanism, we calculate the density profiles, layer thicknesses, and free energies, all as functions of the degree of polymerization and surface coverage. The free energy and the deformation of each layer depend on the compression mechanism, and they can be very different from the ASCF theory. For example, the energy of compression can be as much as three times greater than the analytical SCF (ASCF) prediction, and it does not reduce to simple, universal functions of the reduced distance between the surfaces. The overall physical picture simplifies if the free energy is expressed in terms of the layer deformation, rather than the reduced surface separation. We also examine and quantify the interpenetration of layers, discuss why ASCF theory applies better to some compression mechanisms than others, and end with comments on the difficulties in extracting quantitative information from surface‐forces experiments.

Comparisons of forces of compression in a good solvent for the three different systems, as functions of D/nb. The lower three curves are for σ* = 3, and the upper three are for σ* = 23.

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Comparisons of forces of compression in a good solvent for the three different systems, as functions of D/nb. The lower three curves are for σ* = 3, and the upper three are for σ* = 23.
A new planar‐type dielectric resonator using LTCC technology for mm‐wave band applications
Authors: Kim Sanghee , Yim Jounghyun , Kim Bumman
Published: February 2005

A new planar‐type dielectric resonator (PDR) with a high unloadedQhas been developed using LTCC Technology. The PDR consists of two different dielectric constant materials, high dielectric LTCC cavity (ϵr= 36) acting as a resonator and low dielectric LTCC layer (ϵr= 5.2) surrounding the cavity. Also, the layer has staggered air holes on the top and bottom of the resonator instead of the air cavity of the original PDR, a hollow patch center ground plane at the middle, and shielded cavity metals. The newly realized PDR structure shows a high unloadedQof about 6212 at 37.3 GHz and the measured results are in good agreement with the simulated ones. The PDR can be easily integrated into a planar circuit and can be applicable to mm‐wave band systems. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 533–536, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20688