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21.
Immunohistochemical localization of hTERT protein in human tissues 总被引:12,自引:1,他引:11
Yan P Benhattar J Seelentag W Stehle JC Bosman FT 《Histochemistry and cell biology》2004,121(5):391-397
22.
PJ?MumbyEmail author JD?Hedley JRM?Chisholm CD?Clark H?Ripley J?Jaubert 《Coral reefs (Online)》2004,23(2):171-183
Trends in coral cover are widely used to indicate the health of coral reefs but are costly to obtain from field survey over large areas. In situ studies of reflected spectra at the coral surface show that living and recently dead colonies can be distinguished. Here, we investigate whether such spectral differences can be detected using an airborne remote sensing instrument. The Compact Airborne Spectrographic Imager (Itres Research Ltd, Canada) was flown in two configurations: 10 spectral bands with 1-m2 pixels and 6 spectral bands with 0.25-m2 pixels. First, we show that an instrument with 10 spectral bands possesses adequate spectral resolution to distinguish living Porites, living Pocillopora spp., partially dead Porites, recently dead
Porites (total colony mortality within 6 months), old dead (>6 months) Porites,
Halimeda spp., and coralline red algae when there is no water column to confuse spectra. All substrata were distinguished using fourth-order spectral derivatives around 538 nm and 562 nm. Then, at a shallow site (Tivaru) at Rangiroa Atoll, Tuamotu Archipelago (French Polynesia), we show that live and dead coral can be distinguished from the air to a depth of at least 4 m using first- and fourth-order spectral derivatives between 562–580 nm. However, partially dead and recently dead Porites
colonies could not be distinguished from an airborne platform. Spectral differences among substrata are then exploited to predict the cover of reef substrata in ten 25-m2 plots at nearby Motu Nuhi (max depth 8 m). The actual cover in these plots was determined in situ using quadrats with a 0.01-m2 grid. Considerable disparity occurred between field and image-based measures of substrate cover within individual 25-m2 quadrats. At this small scale, disparity, measured as the absolute difference in cover between field and remote-sensing methods, reached 25% in some substrata but was always less than 10% for living coral (99% of which consisted of
Porites spp.). At the scale of the reef (all ten 25-m2 quadrats), however, disparities in percent cover between imagery and field data were less than 10% for all substrata and extremely low for some classes (e.g. <3% for living
Porites, recently dead Porites
and Halimeda). The least accurately estimated substrata were sand and coralline red algae, which were overestimated by absolute values 7.9% and 6.6%, respectively. The precision of sampling was similar for field and remote-sensing methods: field methods required 19 plots to detect a 10% difference in coral cover among three reefs with a statistical power of 95%. Remote-sensing methods required 21 plots. However, it took 1 h to acquire imagery over 92,500 m2 of reef, which represents 3,700 plots of 25 m2 each, compared with 3 days to survey 10 such plots underwater. There were no significant differences in accuracy between 1-m2 and 0.25-m2 image resolutions, suggesting that the advantage of using smaller pixels is offset by reduced spectral information and an increase in noise (noise was observed to be 1.6–1.8 times greater in 0.25-m2 pixels). We show that airborne remote sensing can be used to monitor coral and algal cover over large areas, providing that water is shallow and clear, and that brown fleshy macroalgae are scarce, that depth is known independently (e.g. from sonar survey). 相似文献
23.
Dincq S Bosman F Buyse MA Degrieck R Celis L de Boer M Van Doorsselaere V Sablon E 《Protein expression and purification》2001,22(1):11-24
The development of recombinant techniques for rapid cloning, expression, and characterization of cDNAs encoding antibody (Ab) subunits has revolutionized the field of antibody engineering. By fusion to heterologous protein domains, chain shuffling, or inclusion of self-assembly motifs, novel molecules such as bispecific Abs can be generated that possess the subset of functional properties designed to fit the intended application. We describe the engineering of Ab fragments produced in bacteria for blocking the CD28-CD80/CD86 costimulatory interaction in order to induce tolerance against transplanted organs. We designed single-chain Fv antibodies, monospecific and bispecific diabodies, and a bispecific tetravalent antibody (BiTAb) molecule directed against the CD80 and/or CD86 costimulatory molecules. These recombinant Ab molecules were expressed in Escherichia coli, followed by purification and evaluation for specific interaction with their respective antigen in an enzyme-linked immunosorbent assay (ELISA). A specific sandwich ELISA confirmed the bispecificity of the bispecific diabodies and the BiTAb. 相似文献
24.
Judith C. A. Cluitmans Carlo Tomelleri Zuhal Yapici Sip Dinkla Petra Bovee-Geurts Venkatachalam Chokkalingam Lucia De Franceschi Roland Brock Giel J. G. C. M. Bosman 《PloS one》2015,10(5)
BackgroundPanthothenate kinase-associated neurodegeneration (PKAN) belongs to a group of hereditary neurodegenerative disorders known as neuroacanthocytosis (NA). This genetically heterogeneous group of diseases is characterized by degeneration of neurons in the basal ganglia and by the presence of deformed red blood cells with thorny protrusions, acanthocytes, in the circulation.ObjectiveThe goal of our study is to elucidate the molecular mechanisms underlying this aberrant red cell morphology and the corresponding functional consequences. This could shed light on the etiology of the neurodegeneration.MethodsWe performed a qualitative and semi-quantitative morphological, immunofluorescent, biochemical and functional analysis of the red cells of several patients with PKAN and, for the first time, of the red cells of their family members.ResultsWe show that the blood of patients with PKAN contains not only variable numbers of acanthocytes, but also a wide range of other misshapen red cells. Immunofluorescent and immunoblot analyses suggest an altered membrane organization, rather than quantitative changes in protein expression. Strikingly, these changes are not limited to the red blood cells of PKAN patients, but are also present in the red cells of heterozygous carriers without neurological problems. Furthermore, changes are not only present in acanthocytes, but also in other red cells, including discocytes. The patients’ cells, however, are more fragile, as observed in a spleen-mimicking device.ConclusionThese morphological, molecular and functional characteristics of red cells in patients with PKAN and their family members offer new tools for diagnosis and present a window into the pathophysiology of neuroacanthocytosis. 相似文献
25.
Olga Perovic Samantha Iyaloo Ranmini Kularatne Warren Lowman Noma Bosman Jeannette Wadula Sharona Seetharam Adriano Duse Nontombi Mbelle Colleen Bamford Halima Dawood Yesholata Mahabeer Prathna Bhola Shareef Abrahams Ashika Singh-Moodley 《PloS one》2015,10(12)
Introduction
We aimed to obtain an in-depth understanding on recent antimicrobial resistance trends and molecular epidemiology trends of S. aureus bacteraemia (SAB).Methods
Thirteen academic centres in South Africa were included from June 2010 until July 2012. S. aureus susceptibility testing was performed on the MicroScan Walkaway. Real-time PCR using the LightCycler 480 II was done for mecA and nuc. SCCmec and spa-typing were finalized with conventional PCR. We selected one isolate per common spa type per province for multilocus sequence typing (MLST).Results
S. aureus from 2709 patients were included, and 1231 (46%) were resistant to methicillin, with a significant decline over the three-year period (p-value = 0.003). Geographical distribution of MRSA was significantly higher in Gauteng compared to the other provinces (P<0.001). Children <5 years were significantly associated with MRSA with higher rates compared to all other age groups (P = 0.01). The most prevalent SCCmec type was SCCmec type III (531 [41%]) followed by type IV (402 [31%]). Spa-typing discovered 47 different spa-types. The five (87%) most common spa-types were t037, t1257, t045, t064 and t012. Based on MLST, the commonest was ST612 clonal complex (CC8) (n = 7) followed by ST5 (CC5) (n = 4), ST36 (CC30) (n = 4) and ST239 (CC8) (n = 3).Conclusions
MRSA rate is high in South Africa. Majority of the isolates were classified as SCCmec type III (41%) and type IV (31%), which are typically associated with hospital and community- acquired infections, respectively. Overall, this study reveals the presence of a variety of hospital-acquired MRSA clones in South Africa dominance of few clones, spa 037 and 1257. Monitoring trends in resistance and molecular typing is recommended to detect changing epidemiological trends in AMR patterns of SAB. 相似文献26.
Sébastien JD Giroux Celmar Alves-Leiva Yann Lécluse Patrick Martin Olivier Albagli Isabelle Godin 《BMC developmental biology》2007,7(1):79
Background
Hematopoietic development in vertebrate embryos results from the sequential contribution of two pools of precursors independently generated. While intra-embryonic precursors harbour the features of hematopoietic stem cells (HSC), precursors formed earlier in the yolk sac (YS) display limited differentiation and self-renewal potentials. The mechanisms leading to the generation of the precursors in both sites are still largely unknown, as are the molecular basis underlying their different potential. A possible approach to assess the role of candidate genes is to transfer or modulate their expression/activity in both sites. We thus designed and compared transduction protocols to target either native extra-embryonic precursors, or hematopoietic precursors. 相似文献27.
Peter JD Andrews Helen Louise Sinclair Claire G Battison Kees H Polderman Giuseppe Citerio Luciana Mascia Bridget A Harris Gordon D Murray Nino Stocchetti David K Menon Haleema Shakur Daniel De Backer 《Trials》2011,12(1):1-13
Background
Severe malaria remains a major cause of global morbidity and mortality. Despite the use of potent anti-parasitic agents, the mortality rate in severe malaria remains high. Adjunctive therapies that target the underlying pathophysiology of severe malaria may further reduce morbidity and mortality. Endothelial activation plays a central role in the pathogenesis of severe malaria, of which angiopoietin-2 (Ang-2) has recently been shown to function as a key regulator. Nitric oxide (NO) is a major inhibitor of Ang-2 release from endothelium and has been shown to decrease endothelial inflammation and reduce the adhesion of parasitized erythrocytes. Low-flow inhaled nitric oxide (iNO) gas is a US FDA-approved treatment for hypoxic respiratory failure in neonates.Methods/Design
This prospective, parallel arm, randomized, placebo-controlled, blinded clinical trial compares adjunctive continuous inhaled nitric oxide at 80 ppm to placebo (both arms receiving standard anti-malarial therapy), among Ugandan children aged 1-10 years of age with severe malaria. The primary endpoint is the longitudinal change in Ang-2, an objective and quantitative biomarker of malaria severity, which will be analysed using a mixed-effects linear model. Secondary endpoints include mortality, recovery time, parasite clearance and neurocognitive sequelae.Discussion
Noteworthy aspects of this trial design include its efficient sample size supported by a computer simulation study to evaluate statistical power, meticulous attention to complex ethical issues in a cross-cultural setting, and innovative strategies for safety monitoring and blinding to treatment allocation in a resource-constrained setting in sub-Saharan Africa.Trial Registration
ClinicalTrials.gov Identifier: NCT01255215 相似文献28.
Food comminution during chewing is the composite result of selection and breakage. In the selection process, every food particle has a chance of being placed between the antagonistic post-canine teeth and being subjected to subsequent breakage. The selection chance, being the ratio between the number of selected and offered particles, has been mathematically described as a function of the number of particles offered, in terms of the number of breakage sites available on the teeth and particle affinity, i.e. the fraction of breakage sites occupied by one particle. The assumption has been made that particles are successively selected during a jaw-closing phase and that the selection chance of subsequent particles having the opportunity to occupy a breakage site proportionally decreases with the unoccupied fraction of the breakage sites left. The number of selected particles of a single size then asymptotically approaches the total number of breakage sites available for that size, when the number of particles offered increases. The critical particle number, derived from the measure of particle affinity, indicates the number of particles by which the breakage sites become saturated. The selection model for single particle sizes has been successfully applied to describe one-chew experiments, using various numbers and sizes of particles made of a silicone-rubber. After pseudo-chewing movements the subjects were unexpectedly instructed to carry out a real chew on particles (half-cubes). Undamaged, hence non-selected half-cubes could afterwards be distinguished from broken particles. The model has been extended to a particle mixture to describe the selection of particles of a certain size while other particles of different sizes are present. If a two-way competition between smaller and larger particles is assumed, the model predicts that the ratios of the selection chances between different particle sizes do not depend upon the numbers of the particles in the mixture. 相似文献
29.
Bosman EA Lawson KA Debruyn J Beek L Francis A Schoonjans L Huylebroeck D Zwijsen A 《Development (Cambridge, England)》2006,133(17):3399-3409
Smad5 is an intracellular mediator of bone morphogenetic protein (Bmp) signalling. It is essential for primordial germ cell (PGC) development, for the development of the allantois and for amnion closure, as demonstrated by loss of Bmp signalling. By contrast, the appearance of ectopic PGC-like cells and regionalized ectopic vasculogenesis and haematopoiesis in thickened Smad5(m1/m1) amnion are amnion defects that have not been associated with loss of Bmp signalling components. We show that defects in amnion and allantois can already be detected at embryonic day (E) 7.5 in Smad5 mutant mice. However, ectopic Oct4-positive (Oct4(+)) and alkaline phosphatase-positive (AP(+)) cells appear suddenly in thickened amnion at E8.5, and at a remote distance from the allantois and posterior primitive streak, suggesting a change of fate in situ. These ectopic Oct4(+), AP(+) cells appear to be Stella negative and hence cannot be called bona fide PGCs. We demonstrate a robust upregulation of Bmp2 and Bmp4 expression, as well as of Erk and Smad activity, in the Smad5 mutant amnion. The ectopic expression of several Bmp target genes in different domains and the regionalized presence of cells of several Bmp-sensitive lineages in the mutant amnion suggest that different levels of Bmp signalling may determine cell fate. Injection of rBMP4 in the exocoelom of wild-type embryos can induce thickening of amnion, mimicking the early amnion phenotype in Smad5 mutants. These results support a model in which loss of Smad5 results paradoxically in gain of Bmp function defects in the amnion. 相似文献
30.
Margaret I Butler Jeremy Gray Timothy JD Goodwin Russell TM Poulter 《BMC evolutionary biology》2006,6(1):42-26