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Considerable Interest (considerable + interest)
Selected AbstractsAstrocytes promote neurogenesis from oligodendrocyte precursor cellsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2006P. M. Gaughwin Abstract The oligodendrocyte precursor cell (OPC) has until recently been regarded as a lineage-restricted precursor cell. Considerable interest has been generated by reports suggesting that OPCs may possess a wider differentiation potential than previously assumed and thus be considered a multipotential stem cell. This study examined the neuronal differentiation potential of rat, postnatal cortical OPCs in response to extracellular cues in vitro and in vivo. OPCs did not exhibit intrinsic neuronal potential and were restricted to oligodendrocyte lineage potential following treatment with the neural precursor mitogen fibroblast growth factor 2. In contrast, a postnatal hippocampal astrocyte-derived signal(s) is sufficient to induce functional neuronal differentiation of cortical OPCs in vitro in population and single cell studies. Co-treatment with Noggin, a bone morphogenetic protein antagonist, did not attenuate neuronal differentiation. Following transplantation to the adult rat hippocampus, cortical OPCs expressed doublecortin, a neuroblast-associated marker. The present findings show that hippocampal, astrocyte-derived signals can induce the neuronal differentiation of OPCs through a Noggin-independent mechanism. [source] Measuring temporal variability in residential magnetic field exposuresBIOELECTROMAGNETICS, Issue 4 2001W.T. Kaune Abstract Considerable interest has developed during the past ten years regarding the hypothesis that living organisms may respond to temporal variability in ELF magnetic fields to which they are exposed. Consequently, methods to measure various aspects of temporal variability are of interest. In this paper, five measures of temporal variability were examined: Arithmetic means (Dmean) and rms values (Drms) of the first differences (i.e., absolute value of the difference between consecutive measurements) of magnetic field recordings; "standardized" forms of Drms, denoted RCMS, obtained by dividing Drms by the standard deviations of the magnetic field data; and mean (Fmean) and rms (Frms) values of fractional first differences. Theoretical investigations showed that Dmean and Drms are virtually unaffected by long-term systematic trends (changes) in exposure. These measures thus provide rather specific measures of short-term temporal variability. This was also true to a lesser extent for Fmean and Frms. In contrast, the RCMS metric was affected by both short-term and long-term exposure variabilities. The metrics were also investigated using a data set consisting of twice-repeated two-calendar-day recordings of bedroom magnetic fields and personal exposures of 203 women residing in the western portion of Washington State. The predominant source of short-term temporal variability in magnetic field exposures arose from the movement of subjects through spatially varying magnetic fields. Spearman correlations between TWA bedroom magnetic fields or TWA personal exposures and five measures of temporal variability were relatively low. Weak to moderate levels of correlation were observed between temporal variability measured during two different sessions separated in time by 3 or 6 months. We conclude that first difference and fractional difference metrics provide specific and fairly independent measures of short-term temporal variability. The RCMS metric does not provide an easily interpreted measure of short-term or long-term temporal variability. This last result raises uncertainties about the interpretation of published studies that use the RCMS metric. Bioelectromagnetics 22:232,245, 2001. © 2001 Wiley-Liss, Inc. [source] Myocardial growth before and after birth: clinical implications,ACTA PAEDIATRICA, Issue 2 2000AM Rudolph Perinatal changes in myocardial growth have recently evoked considerable interest with regard to cardiac chamber development with congenital cardiac lesions and to myocardial development in preterm infants. It is suggested that cardiac chamber development is influenced by blood flow. Experimental pulmonary stenosis in fetal lambs may induce either greatly reduced or markedly increased right ventricular volume. Ventricular enlargement appears to be associated with a large ventricular volume load resulting from tricuspid valve regurgitation. A small competent tricuspid valve is associated with reduced flow through the ventricle due to outflow obstruction and a small right ventricle. Postnatal growth of the ventricles in congenital heart disease is discussed. Increase in myocardial mass prenatally is achieved by hyperplasia, both during normal development and when myocardial mass is increased by right ventricular outflow obstruction. Postnatally, increases in myocardial mass with normal growth, as well as with ventricular outflow obstruction, are largely due to hypertrophy of myocytes. Myocardial capillary numbers do not increase in proportion with myocyte numbers in ventricular myocardium in association with outflow obstruction. The postnatal effects of these changes in congenital heart lesions are considered. Studies in fetal lambs suggest that the late gestational increase in blood cortisol concentrations is responsible for the change in the pattern of myocardial growth after birth. The concern is raised that prenatal exposure of the premature infant to glucocorticoids, administered to the mother to attempt to prevent hyaline membrane disease in the infant, may inhibit myocyte proliferation and result in a heart with fewer than normal myocytes. This would necessitate that each myocyte would have to hypertrophy abnormally to achieve a normal cardiac mass postnatally. [source] Establishment of a chick embryo model for analyzing liver development and a search for candidate genesDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 6 2005Yuji Yokouchi The liver plays a crucial role in metabolism. There is considerable interest in how the liver develops, as such knowledge could prove of importance in regenerative medicine. However, our understanding of liver development remains somewhat limited. We have developed a model system using the chick embryo that is cost effective and is easy to manipulate experimentally. We performed four fundamental studies: (i) construction of an atlas of the developing chick liver; (ii) identification of differentiation marker genes in the developing chick embryo; (iii) development of germ-layer specific electroporation; and (iv) establishment of organ culture from the developing chick liver. Using this system, we have been able to demonstrate the functions of candidate genes within a shorter period and in a more cost-effective manner. In parallel with the establishment of this system, we examined the expression patterns of genes known to be required for organ development in the developing chick embryo in order to identify genes also involved in liver development. To date, we have found sixteen genes that are expressed in the developing chick liver (GELD, genes expressed in liver development). This knowledge will be fundamental to the establishment of the basic technology for engineering liver tissue in the future. [source] Syllable repertoire and the size of the song control system in captive canaries (Serinus canaria)DEVELOPMENTAL NEUROBIOLOGY, Issue 1 2004Stefan Leitner Abstract In songbirds, there is considerable interest in relationships between song structure and the size of the song control system in the forebrain. In male canaries, earlier studies have reported that repertoire size increased with age, and positive correlations were obtained between repertoire size and the volume of song control nuclei such as high vocal center (HVC). Here we investigate whether age has an effect upon both the song structure and the morphology of two song control nuclei [HVC and robustus archistriatalis (RA)] that are important in song production. We recorded songs from an aviary population of 1- and 2-year-old male domesticated canaries. We found that repertoire size, number of sexually attractive (sexy) syllables, and size of song nuclei did not differ between 1- and 2-year-old males. Neither did we find significant correlations between syllable repertoire size and the size of the song control nuclei. However, HVC size was positively correlated with the proportion of sexy syllables in the repertoires of 2-year-old males. Some older males may enhance vocal performance by modifying the control of syllables rather than by increasing repertoire size or neural space. © 2004 Wiley Periodicals, Inc. J Neurobiol 60: 21,27, 2004 [source] Comparison of two glutaraldehyde immobilization techniques for solid-phase tryptic peptide mapping of human hemoglobin by capillary zone electrophoresis and mass spectrometryELECTROPHORESIS, Issue 9 2004Isabelle Migneault Abstract Stabilization of proteolytic enzymes, especially by immobilization, is of considerable interest because of their potential applications in medicine and the chemical and pharmaceutical industries. We report here a detailed comparison of two procedures for trypsin immobilization using the same homobifunctional agent, glutaraldehyde, for the purpose of peptide mapping. These methods include covalent coupling either to controlled pore glass (solid support) or via a cross-linking reaction (without any solid support). The immobilized trypsin preparations were characterized by the determination of immobilization efficiency, which ranged from 68 to > 95%, and measurement of apparent kinetic parameters toward a synthetic peptide-like substrate. Batch digestions of whole denaturated human normal adult hemoglobin (HbA) were performed to obtain peptide maps by capillary zone electrophoresis (CZE). Migration time reproducibility of the CZE maps was excellent, with a mean relative standard deviation of 1.5%. Moreover, the two immobilized enzyme preparations showed excellent reproducibility for repeated digestions. Matrix-assisted laser desorption/ionization (MALDI)-mass spectrometry was also used for peptide mass mapping of denaturated HbA digested using the two immobilized trypsin preparations. Even though the two immobilized trypsin preparations do not behave identically, similar sequence coverages of 57% and 61% (for the two HbA chains merged) were achieved for the support-based and cross-linked trypsin preparations, respectively. [source] Degradation of nonylphenol ethoxylates in estuarine sediment under aerobic and anaerobic conditionsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2003P. Lee Ferguson Abstract Nonylphenol ethoxylate (NPEO) surfactants and their metabolites are ubiquitous contaminants of the aquatic environment. Despite considerable interest in the environmental fate of these compounds due to concerns over toxicity and estrogenic activity, the pathways of NPEO degradation in sediments have not previously been reported, in spite of the fact that sediment appears to be an important sink for these compounds in the environment. In the present work, we have examined the rates and pathways of NPEO degradation in batch sediment slurry experiments using radiolabeled NPEO mixtures. Results suggest that NPEOs are more persistent in sediments under anaerobic conditions than in the presence of oxygen. In addition, it was illustrated that NPEO degradation proceeds via separate pathways in oxic and anoxic sediment. Discernible metabolites were identified and an overall mass balance for NPEO degradation in oxic and anoxic sediment was achieved. In contrast with previous studies, no evidence was observed for net production of nonylphenol from NPEOs during aerobic or anaerobic degradation. The observed relative rates at which NPEO ethoxymers disappeared in the sediment slurry experiments were consistent with previous reports for these compounds in sediment and other environmental media, although the absolute rates measured were somewhat faster than those reported for field sediments. [source] Mesenchymal stem cell therapy in equine musculoskeletal disease: scientific fact or clinical fiction?EQUINE VETERINARY JOURNAL, Issue 2 2007S. E. TAYLOR Summary The goal in the therapeutic use of mesenchymal stem cells (MSCs) in musculoskeletal disease is to harness the regenerative nature of these cells focussing on their potential to grow new tissues and organs to replace damaged or diseased tissue. Laboratory isolation of MSCs is now well established and has recently been demonstrated for equine MSCs. Stem cell science has attracted considerable interest in both the scientific and clinical communities because of its potential to regenerate tissues. Research into the use of MSCs in tissue regeneration in general reflects human medical needs, however, the nature, prevalence and prognosis of superficial digital flexor tendonitis has put equine veterinary science at the forefront of tendon regeneration research. Much has been investigated and learnt but it must be appreciated that in spite of this, the field is still relatively young and both communities must prepare themselves for considerable time and effort to develop the technology into a highly efficient treatments. The promise of functional tissue engineering to replace old parts with new fully justifies the interest. At present, however, it is important to balance the understanding of our current limitations with a desire to progress the technology. [source] Areca nut use following migration and its consequencesADDICTION BIOLOGY, Issue 1 2002S. Warnakulasuriya The combined use of areca nut and smokeless tobacco (ST) is practiced particularly in the Indo-Chinese continents. While there is considerable global variation in the use of these products, migrant studies relevant to areca nut use is of considerable interest to epidemiologists in suggesting the extent to which these environment exposures are important in the aetiology of different cancers and other health-related consequences. Studies on Indian migrants to the Malay peninsula, South and east Africa and various Asian ethnic groups resident in several parts of the United Kingdom have shown that the consumption of areca nut (often mixed with ST) is highly prevalent in these communities. Available data on the prevalence of areca chewing among these migrant populations are reviewed here. The carriage of these risk factors from South Asia to other countries has resulted in excess risk of oral cancer in these new settlements. There is also a high incidence of cardiovascular disease, hypertension and late onset diabetes among Indians living in the United Kingdom and there is new evidence to suggest that the combined roles of areca and ST may be contributory. Because of their enhanced financial situation, substance abuse may increase in their new country of domicile. The two products are psychologically addictive and a dependency syndrome related to their use among Asian immigrants to the United Kingdom has been described recently. [source] Identification of brain neurons expressing the dopamine D4 receptor gene using BAC transgenic miceEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2006Daniela Noaín Abstract The dopamine D4 receptor (D4R) has received considerable interest because of its higher affinity for atypical antipsychotics, the extremely polymorphic nature of the human gene and the genetic association with attention deficit and hyperactivity disorder (ADHD). Several efforts have been undertaken to determine the D4R expression pattern in the brain using immunohistochemistry, binding autoradiography and in situ hybridization, but the overall published results present large discrepancies. Here, we have explored an alternative genetic approach by studying bacterial artificial chromosome (BAC) transgenic mice that express enhanced green fluorescent protein (EGFP) under the transcriptional control of the mouse dopamine D4 receptor gene (Drd4). Immunohistochemical analysis performed in brain sections of Drd4 -EGFP transgenic mice using an anti-EGFP polyclonal antibody showed that transgenic expression was predominant in deep layer neurons of the prefrontal cortex, particularly in the orbital, prelimbic, cingulate and rostral agranular portions. In addition, discrete groups of Drd4 -EGFP labelled neurons were observed in the anterior olfactory nucleus, ventral pallidum, and lateral parabrachial nucleus. EGFP was not detected in the striatum, hippocampus or midbrain as described using other techniques. Given the fine specificity of EGFP expression in BAC transgenic mice and the high sensitivity of the EGFP antibody used in this study, our results indicate that Drd4 expression in the adult mouse brain is limited to a more restricted number of areas than previously reported. Its leading expression in the prefrontal cortex supports the importance of the D4R in complex behaviours depending on cortical dopamine (DA) transmission and its possible role in the etiopathophysiology of ADHD. [source] Variable carbon recovery of Walkley-Black analysis and implications for national soil organic carbon accountingEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 6 2007S. Lettens Summary There is considerable interest in the computation of national and regional soil carbon stocks, largely as the result of the provisions of the Kyoto Protocol. Such stocks are often calculated and compared without proper reference to the uncertainties induced by different analytical methodologies. We illustrate the nature and magnitude of these uncertainties with the present soil organic carbon (SOC) study in Belgium. The SOC recovery of the Walkley-Black method was investigated based on a database of 475 samples of silt loam and sandy soils, which cover different soil depths and vegetation types in northern Belgium. The organic carbon content of the soil samples was measured by the original Walkley-Black method and by a total organic carbon analyser. The recovery was computed as the ratio of these two results per soil sample. Land use, texture and soil sampling depth had a significant influence on the recovery as well as their three-way interaction term (land use × texture × sampling depth). The impact of a land use, texture and sampling depth dependent Walkley-Black correction on the year 2000 SOC inventory of Belgium was determined by regression analysis. Based on new correction factors, the national SOC stocks increased by 22% for the whole country, ranging from 18% for cropland to 31% for mixed forest relative to the standard corrected SOC inventory. The new recovery values influenced therefore not only C stocks in the year 2000, but also the expected SOC change following land use change. Adequate correction of Walkley-Black measurements is therefore crucial for the absolute and comparative SOC assessments that are required for Kyoto reporting and must be computed to take into account the regional status of soil and land use. ,Universal' corrections are probably an unrealistic expectation. [source] PHENOTYPIC PLASTICITY OF HERMAPHRODITE SEX ALLOCATION PROMOTES THE EVOLUTION OF SEPARATE SEXES: AN EXPERIMENTAL TEST OF THE SEX-DIFFERENTIAL PLASTICITY HYPOTHESIS USING SAGITTARIA LATIFOLIA (ALISMATACEAE)EVOLUTION, Issue 4 2008Marcel E. Dorken Separate sexes can evolve under nuclear inheritance when unisexuals have more than twice the reproductive fitness of hermaphrodites through one sex function (e.g., when females have more than twice the seed fertility of hermaphrodites). Because separate sexes are thought to evolve most commonly via a gynodioecious intermediate (i.e., populations in which females and hermaphrodites cooccur), the conditions under which females can become established in populations of hermaphrodites are of considerable interest. It has been proposed that resource-poor conditions could promote the establishment of females if hermaphrodites are plastic in their sex allocation and allocate fewer resources to seed production under these conditions. If this occurs, the seed fertility of females could exceed the doubling required for the evolution of unisexuality under low-, but not high-resource conditions (the sex-differential plasticity hypothesis). We tested this hypothesis using replicate experimental arrays of the aquatic herb Sagittaria latifolia grown under two fertilizer treatments. The results supported the sex-differential plasticity hypothesis, with females having more than twice the seed fertility of hermaphrodites under low-, but not high-fertilizer conditions. Our findings are consistent with the idea that separate sexes are more likely to evolve under unfavorable conditions. [source] A comparative study of the asparagine-linked oligosaccharides on siglec-5, siglec-7 and siglec-8, expressed in a CHO cell line, and their contribution to ligand recognitionFEBS JOURNAL, Issue 5 2001Sylvie Freeman The siglecs (sialic acid-binding immunoglobulin-like lectins) mediate sialic acid-dependent cellular interactions and may in some cases signal through SH2-binding domains. In addition to the previously characterized siglecs, sialoadhesin, CD22, CD33 and myelin-associated glycoprotein, several new ones, siglec-5, siglec-7 and siglec-8, have recently been cloned. Although these novel receptors have generated considerable interest as therapeutic targets because of their expression pattern on immune cells, very little is known about how their lectin activity is regulated. Previous studies with sialoadhesin, CD22 and CD33 have shown that siglec glycosylation has significant effects on binding. To determine any differences in the glycan composition of siglec-5, siglec-7 and siglec-8 that may modify their function, we released and characterized the N-linked oligosaccharide distribution in these three glycoproteins. The glycan pools from siglec-5 and siglec-7 contained a larger proportion of sialylated and core-fucosylated biantennary, triantennary and tetra-antennary oligosaccharides, whereas the carbohydrate mixture released from siglec-8 is noticeably less sialylated and is more abundant in ,high-mannose'-type glycans. In addition, we show that, in contrast with CD22 and CD33, mutating the conserved potentially N-linked glycosylation site in the first domain has no effect on binding mediated by siglec-5 or siglec-7. [source] The prothrombin gene is expressed in the rat kidneyFEBS JOURNAL, Issue 1 2000Implications for urolithiasis research There is considerable interest in determining the role of prothrombin fragments, especially urinary prothrombin fragment 1 (UPTF1), in the pathogenesis of calcium oxalate (CaOx) urinary calculi. This fragment is present in abundance in the matrix of CaOx crystals generated in human urine in vitro and has also been detected in human urinary stones containing calcium. More recently, prothrombin gene expression has been reported in the human kidney. However, studies examining the renal biosynthesis of prothrombin or perhaps only its fragments during experimental lithogenesis, and in consequence, the role of UPTF1 in stone formation, cannot be carried out in humans. The aim of this investigation therefore was to determine whether prothrombin gene expression is present in the rat kidney. Total RNA was isolated from the kidneys and livers of 12 rats. Using reverse transcriptase PCR, mRNAs corresponding to the thrombin and fragment 1 + 2 (F1+2) regions of prothrombin were analysed by agarose gel electrophoresis. The expression of glyceraldehyde 3-phosphate dehydrogenase was also examined to determine whether the quality of the tissue mRNAs was adequate for analyses. The amplified products were identified by sequence analysis. All kidneys displayed evidence of expression of the thrombin and F1+2 domains of the prothrombin gene. Furthermore, the sequences of these PCR-derived products from kidney were identical to those from liver. This suggests that the prothrombins secreted by these two organs are identical. The fact that prothrombin biosynthesis occurs in both the human and rat kidney presents an opportunity for using established rat models of stone disease to evaluate the influence of lithogenic conditions on prothrombin gene expression, and the potential role of UPTF1 in vivo. [source] High-Resolution Patterning of Hydrogels in Three Dimensions using Direct-Write Photofabrication for Cell GuidanceADVANCED FUNCTIONAL MATERIALS, Issue 22 2009Stephanie K. Seidlits Abstract The development of three-dimensional, spatially defined neuronal cultures that mimic chemical and physical attributes of native tissue is of considerable interest for various applications, including the development of tailored neuronal networks and clinical repair of damaged nerves. Here, the use of multiphoton excitation to photocrosslink protein microstructures within three-dimensional, optically transparent hydrogel materials, such as those based on hyaluronic acid, is reported. Multiphoton excitation confines photocrosslinking to a three-dimensional voxel with submicron spatial resolution, enabling fabrication of protein matrices with low- to sub-micrometer feature sizes by scanning the focus of a laser relative to the reagent solution. These methods can be used to create complex three-dimensional architectures that provide both chemical and topographical cues for cell culture and guidance, providing for the first time a means to direct cell adhesion and migration on size scales relevant to in vivo environments. Using this approach, guidance of both dorsal root ganglion cells (DRGs) and hippocampal neural progenitor cells (NPCs) along arbitrary, three-dimensional paths is demonstrated. [source] Synthetic Strategies for Controlling the Morphology of Proton Conducting Polymer Membranes,,FUEL CELLS, Issue 2 2005Y. Yang Abstract The nanostructure and morphology of proton conducting polymers is of considerable interest in the search for next generation materials and optimization of existing ones. Synthetic methodologies for tailoring molecular structures that promote nanoscopic phase separation of ionic and non-ionic domains, and the effect of phase separation on parameters such as proton conductivity, are considered. Rather than distinguish proton conducting polymers according to chemical class, they are categorized under sub-headings of random, block, and graft copolymers. The synthetic methodology available to access archetypal polymer structures is dependent on the nature of the monomers and restrictive compared to conventional non-ionic polymer systems. Irrespective of the methodology, ionic aggregation and phase separation are consistently found to play an important role in the proton conductivity of low ion exchange capacity,(IEC) membranes, but less of a role in high IEC membranes. Significant research is required to further develop relationships between polymer architecture, morphology, and electrolytic properties. [source] Functional trait variation and sampling strategies in species-rich plant communitiesFUNCTIONAL ECOLOGY, Issue 1 2010Christopher Baraloto Summary 1. ,Despite considerable interest in the application of plant functional traits to questions of community assembly and ecosystem structure and function, there is no consensus on the appropriateness of sampling designs to obtain plot-level estimates in diverse plant communities. 2. ,We measured 10 plant functional traits describing leaf and stem morphology and ecophysiology for all trees in nine 1-ha plots in terra firme lowland tropical rain forests of French Guiana (N = 4709). 3. ,We calculated, by simulation, the mean and variance in trait values for each plot and each trait expected under seven sampling methods and a range of sampling intensities. Simulated sampling methods included a variety of spatial designs, as well as the application of existing data base values to all individuals of a given species. 4. ,For each trait in each plot, we defined a performance index for each sampling design as the proportion of resampling events that resulted in observed means within 5% of the true plot mean, and observed variance within 20% of the true plot variance. 5. ,The relative performance of sampling designs was consistent for estimations of means and variances. Data base use had consistently poor performance for most traits across all plots, whereas sampling one individual per species per plot resulted in relatively high performance. We found few differences among different spatial sampling strategies; however, for a given strategy, increased intensity of sampling resulted in markedly improved accuracy in estimates of trait mean and variance. 6. ,We also calculated the financial cost of each sampling design based on data from our ,every individual per plot' strategy and estimated the sampling and botanical effort required. The relative performance of designs was strongly positively correlated with relative financial cost, suggesting that sampling investment returns are relatively constant. 7. ,Our results suggest that trait sampling for many objectives in species-rich plant communities may require the considerable effort of sampling at least one individual of each species in each plot, and that investment in complete sampling, though great, may be worthwhile for at least some traits. [source] Clinical pharmacology and therapeutic use of antioxidant vitaminsFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 2 2007Ramón Rodrigo Abstract The clinical use of antioxidants has gained considerable interest during the last decade. It was suggested from epidemiological studies that diets high in fruits and vegetables might help decrease the risk of cardiovascular disease. Therefore, supplements of vitamins C and E were applied through protocols aimed to prevent diseases such as atherosclerosis, preeclampsia or hypertension, thought to be mediated by oxidative stress. Despite the biological properties of these vitamins could account for an effective protection, as shown by several clinical and experimental studies, their efficacy remains controversial in the light of some recent clinical trials and meta-analyses. However, the methodology of these studies, criteria for selection of patients, the uncertain extent of progression of the disease when initiating supplementation, the lack of mechanistic studies containing basic scientific aspects, such as the bioavailability, pharmacokinetic properties, and the nature of the antioxidant sources of vitamins, could account for the inconsistency of the various clinical trials and meta-analyses assessing the efficacy of these vitamins to prevent human diseases. This review presents a survey of the clinical use of antioxidant vitamins E and C, proposing study models based on the biological effects of these compounds likely to counteract the pathophysiological mechanisms able to explain the structural and functional organ damage. [source] Polymer Films Composed of Surface-Bound Nanofilaments with a High Aspect Ratio, Molecularly Imprinted with Small Molecules and ProteinsADVANCED FUNCTIONAL MATERIALS, Issue 8 2009Ana Valvanuz Linares Abstract Hierarchically nanostructured materials that combine two or more levels of structuring and that exhibit a combination of useful features have gained considerable interest over recent years. Here, the generation of surface-bound nanofilaments with a high aspect ratio by nanomolding on a nanoporous template surface is described. The filaments, at the same time, carry molecularly imprinted binding sites. The dye fluorescein and the protein myoglobin are used as model templates for imprinting. The surfaces exhibit specific binding as revealed by fluorescence microscopy. The wetting properties of the surfaces depend on the dimensions of the nanofilaments and on the nature of the polymer. It is believed that these materials can potentially be useful for applications in biosensors and biochips. [source] Observation of Structural and Conductance Transition of Rotaxane Molecules at a Submolecular Scale,ADVANCED FUNCTIONAL MATERIALS, Issue 5 2007M. Feng Abstract Rotaxane molecules have attracted considerable interest because of their good performance in both molecular electronic devices and nanoscale data-storage media. Low-temperature scanning tunneling microscopy is used to investigate the structure and conductance of single H2 rotaxane molecules on a buffer-layered Au(111) substrate at 77,K. It is demonstrated that the conductance switching in rotaxane-based, solid-state devices is an inherent property of the rotaxane molecules. These results provide evidence that the conductance switching might arise from the movement of the cyclobis(paraquat- p -phenylene) ring along the rod section of the dumbbell-shaped backbone of the rotaxane molecule. [source] More than technology and access: primary care patients' views on the use and non-use of health information in the Internet ageHEALTH & SOCIAL CARE IN THE COMMUNITY, Issue 2 2004Anne Rogers MSc(Econ) PhD Abstract Over the past decade, there has been considerable interest in the transmission of health information made available though the Internet with increasing confidence being placed in the potential power of the Internet to transform communication, clinical practice and relationships with patients. Subsequent to the failure of a primary-care-based initiative designed to provide free assistance and access to health information via the Internet, a survey was conducted. Findings from this survey suggested that facilitating access to e-information is necessary, but not in itself sufficient, to encourage current non-users to start exploring the Internet. The qualitative study reported here was aimed at exploring the way in which people use and perceive the utility of Internet information for managing health and illness and engaging with the health service system. Data was gathered from two sources. Interviews and observations of a sample who had used a free primary-care-based Internet service (n = 5) and interviews with a sample drawn from a survey of patient attitudes to using the Internet for health information (n = 12). The less-considered aspects of access and the use of e-information for health matters related to the varied existing relationships respondents had to computers, health information and health professionals. One of the main reasons why some respondents do not use the Internet to access health information is related to a lack of perceived utility and pertinence of such information for managing their healthcare. The optimal and equitable use of the Internet as a means of complimenting health-service utilisation will not emerge merely from increasing access to e-information. The potential for narrowing or increasing inequality between the information rich and poor needs to be viewed in a broader psychosocial context. The latter includes the nature of existing relationships which people have with the health service and the value that people place on their own capacity to make use of information in managing their healthcare. [source] Pathogenesis of Helicobacter pylori InfectionHELICOBACTER, Issue 2005Céu Figueiredo ABSTRACT As with many infectious diseases, only a fraction of people infected with Helicobacter pylori develop clinical disease, and host genetics, host immune response, and bacterial virulence factors appear to play critical roles. There has been considerable interest in putative bacterial virulence factors and, while several have been identified, it is not clear whether they act independently or in concert. Disease associations have been proposed for the cag pathogenicity island (PAI), vacA, and genes encoding outer membrane proteins (OMPs). Numerous studies published in the last year have provided new insights into the function of these putative virulence factors in gastroduodenal pathogenesis. This article will review the recent novel findings (from April 2004) for the roles of the putative disease-associated virulence factors as well as their interaction with host. [source] Analysis and comparison of morphological reconstructions of hippocampal field CA1 pyramidal cellsHIPPOCAMPUS, Issue 3 2005José Ambros-Ingerson Abstract Morphological reconstructions have become a routine and valuable tool for neuroscientists. The accuracy of reconstructions is a matter of considerable interest given that they are widely used in computational studies of neural function. Despite their wide usage, comparisons of reconstructions obtained using various methodologies are lacking. We reviewed reconstructions of hippocampal CA1 pyramidal cells from five published studies and found marked differences in some of the most basic measurements. For four of the five studies means of total cell length clustered in the 11,479,13,417-,m range. The remaining study had a significantly larger value for this index at 16,992 ± 5,788 ,m. Surface area means varied more than 4-fold from 16,074 to 67,102 ,m2. Volume means varied more than 8-fold from 3,828 to 30,384 ,m3. Simulated passive input resistance means varied from 38.0 to 172.1 M,, reflecting the variability in cell dimensions. Estimates of the electrotonic length varied from 1.26 to 1.56. In two reconstructions used in previously published studies, simulated somatic excitatory postsynaptic potentials (EPSPs) varied 2,4-fold in amplitude, time to peak and half-width, for synaptic inputs at similar locations. Substantial jitter on the z -axis was identified as one likely source of the discrepancy in total cell length, while substantial differences in diameter measurements across studies, and sometimes within the same study, accounted for the variability in surface area and volume. While some part of the observed variability is surely due to the diversity of CA1 pyramidal cells, our analysis suggests that a substantial portion stemmed from methodological inconsistencies and from technological limitations. Suggestions are made for improving the quality and usefulness of morphological reconstructions. We conclude that reconstructions across studies have substantial variability in measures that are very relevant to neuronal function. Consequently, modelers are advised to use more than just one reconstructed cell in their simulations of neural function. © 2004 Wiley-Liss, Inc. [source] French Views on Thatcherism and BlairismHISTORICAL RESEARCH, Issue 182 2000Jacques Leruez The French like terms ending in ,ism', especially when they appear to represent a substantial ideological proposition or, at the very least, a definite change in the methods of governance. Thus, both Thatcherism and Blairism have held considerable interest for both the educated public and the media. If Thatcherism was generally condemned as reactionary, there was none the less a certain amount of admiration for Lady Thatcher's ,conviction'. As for Blairism, while considered a betrayal of socialist ideals by the more traditional left wing, it is looked upon with some sympathy in centrist and even right-wing circles. [source] Multiple Functionalities of Polyelectrolyte Multilayer Films: New Biomedical ApplicationsADVANCED MATERIALS, Issue 4 2010Thomas Boudou Abstract The design of advanced functional materials with nanometer- and micrometer-scale control over their properties is of considerable interest for both fundamental and applied studies because of the many potential applications for these materials in the fields of biomedical materials, tissue engineering, and regenerative medicine. The layer-by-layer deposition technique introduced in the early 1990s by Decher, Moehwald, and Lvov is a versatile technique, which has attracted an increasing number of researchers in recent years due to its wide range of advantages for biomedical applications: ease of preparation under "mild" conditions compatible with physiological media, capability of incorporating bioactive molecules, extra-cellular matrix components and biopolymers in the films, tunable mechanical properties, and spatio-temporal control over film organization. The last few years have seen a significant increase in reports exploring the possibilities offered by diffusing molecules into films to control their internal structures or design "reservoirs," as well as control their mechanical properties. Such properties, associated with the chemical properties of films, are particularly important for designing biomedical devices that contain bioactive molecules. In this review, we highlight recent work on designing and controlling film properties at the nanometer and micrometer scales with a view to developing new biomaterial coatings, tissue engineered constructs that could mimic in vivo cellular microenvironments, and stem cell "niches." [source] Laparoscopic pancreatic surgery: a review of present results and future prospectsHPB, Issue 4 2010Omer S. Al-Taan Abstract Pancreatic surgery is still associated with a relatively high morbidity and mortality compared with other specialties. This is a result of the complex nature of the organ, the difficult access as a result of the retroperitoneal position and the number of technically challenging anastomoses required. Nevertheless, the past two decades have witnessed a steady improvement in morbidity and a decrease in mortality achieved through alterations of technique (particularly relating to the pancreatic anastomoses) together with hormonal manipulation to decrease pancreatic secretions. Recently minimally invasive pancreatic surgery has been attempted by several centres around the world which has stimulated considerable interest in this approach. The majority of the cases attempted have been distal pancreatectomies, because of the more straightforward nature of the resection and the lack of a pancreatic ductal anastomosis, but more recently reports of laparoscopic pancreaticoduodenectomy have started to appear. The reports of the series to date have been difficult to interpret and although the results are claimed to be equivalent or better than those associated with a traditional approach a careful examination of the literature and comparison with the best results previously reported does not presently support this. In the present review we examined all the reports of pancreatic procedures performed laparoscopically and compared the results with those previously achieved at open surgery. [source] Melatonin and ulcerative colitis: Evidence, biological mechanisms, and future researchINFLAMMATORY BOWEL DISEASES, Issue 1 2009Paul D. Terry PhD Abstract Ulcerative colitis (UC) is an inflammatory bowel disease that afflicts up to 1 million people in the US. Current treatments for UC are mostly nonspecific, not always effective, and often accompanied by serious side effects. Therefore, there is considerable interest in finding alternative and more tolerable treatments for this disease. Physiologic data suggest that melatonin is an important regulator of both inflammation and motility in the gastrointestinal tract, and data from in vitro studies, animal experiments, and limited studies in humans suggest that supplemental melatonin may have an ameliorative effect on colitis. In this review we summarize the evidence regarding melatonin as a possible therapeutic agent in UC and discuss possible biological mechanisms and directions for future research. (Inflamm Bowel Dis 2008) [source] On MILES based on flux-limiting algorithms,INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 10-11 2005F. F. Grinstein Abstract Non-classical large eddy simulation (LES) approaches based on using the unfiltered flow equations instead of the filtered ones have been the subject of considerable interest during the last decade. In the monotonically integrated LES (MILES) approach, flux-limiting schemes are used to emulate the characteristic turbulent flow features in the high-wave number end of the inertial subrange region. Mathematical and physical aspects of implicit sub grid scale modelling using nonlinear flux-limiters are conveniently addressed using the modified LES-equation formalism. In this study, the performance of MILES is demonstrated as a function of the flux-limiting scheme in selected representative case studies. Published in 2005 by John Wiley & Sons, Ltd. [source] The MUC1 oncoprotein as a functional target: Immunotoxin binding to ,/, junction mediates cell killingINTERNATIONAL JOURNAL OF CANCER, Issue 1 2009Daniel B. Rubinstein Abstract MUC1, a heavily glycosylated mucin, has generated considerable interest as a target for tumor killing because of its overexpression in malignancies. Full-length MUC1 (MUC1/TM) is proteolytically cleaved after synthesis generating , and , subunits, which specifically bind in a noncovalent interaction. Although the , chain remains on the cell surface, the , chain binds in an on-and-off interaction. Most anti-MUC1 antibodies (Abs) described to date recognize epitopes within the highly immunogenic ,-chain tandem repeat. Because the ,-chain is shed, such Abs are sequestered and fail to reach MUC1-expressing cells. Immunizing with cDNA encoding MUC1/TM and the spliced MUC1/X isoform from which the tandem repeat has been deleted yielded antibodies to the MUC1 ,/, junction. Pseudomonas toxin PE38 linked to polyclonal anti-MUC1 ,/, junction Abs both bound and killed MUC1-positive malignant cells. Monoclonal DMC209 binds the MUC1 ,/, junction in both MUC1/X and MUC1/TM. When injected into SCID mice xenotransplanted with human breast cancer MDA-MB-231, monoclonal DMC209 showed significant in vivo tumor-suppressive activity. The MUC1/X ,/, junction presents a biologically-significant target in MUC1-expressing malignancies because (i) antibodies directed against cell-bound ,/, junction epitopes reach the intended cellular target, (ii) antibodies to junction epitope are internalized into cells, (iii) anti ,/, junction antibodies can effectively kill high MUC1-expressing cancer cells as antibody-toxin conjugates and (iv) antibodies targeting the MUC1 cell-bound ,/, junction results in tumor suppression in vivo. Our results indicate that cell-bound MUC1 ,/, junction, unlike shed alpha chain, represents a highly effective moiety for targeting and killing MUC1-expressing malignancies. © 2008 Wiley-Liss, Inc. [source] Detection of bone marrow-disseminated breast cancer cells using an RT-PCR assay of MUC5B mRNAINTERNATIONAL JOURNAL OF CANCER, Issue 4 2003Nora Berois Abstract The evaluation of disseminated epithelial tumor cells in breast cancer patients has generated considerable interest due to its potential association with disease recurrence. Our work was performed to analyze the usefulness of 5 mucin genes expression (MUC2, MUC3, MUC5B, MUC6 and MUC7), using RT-PCR assays, to detect disseminated cancer cells in patients with operable breast cancer. The highest frequencies of positive RT-PCR tests in breast tumor extracts were observed for MUC5B (7/15) and MUC7 (5/12). The best specificity, negative results on all peripheral blood mononuclear (PBMN) cell samples from healthy donors, were shown for MUC2, MUC5B and MUC6 RT-PCR assays. Thus, we selected MUC5B as a target gene for further evaluation. Using a nested RT-PCR, MUC5B mRNA transcripts were detected in 16/31 primary breast tumors (but not in 36 samples of normal PBMN cells) and in the human MCF-7 breast cancer cell line but not in BT20, MDA, T47D and ZR-75 breast cancer cell lines, indicating that MUC5B mRNA is expressed in a population of breast cancer cells. Using this method, 9/46 patients (19.5%) who underwent curative surgery showed positive MUC5B mRNA in bone marrow aspirates obtained prior to surgery, including 5/24 patients (20.8%) with stage I or II breast cancer, without histopathologic lymph node involvement. These results indicate that MUC5B mRNA could be a specific marker applicable to the molecular diagnosis of breast cancer cell dissemination. A comparative evaluation between MUC5B mRNA, cytokeratin 19 (CK19) mRNA and carcinoembryonic antigen (CEA) mRNA in all bone marrow aspirates suggests a putative complementation for molecular detection of disseminated carcinoma cells. Considering that breast cancer is characterized by a great phenotypic heterogeneity, the use of multimarker approach could contribute to tumor cell detection in bone marrow and blood. © 2002 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||||||||||||||||||||||||||||||||