849 research outputs found
Para-fluorination of anilides using electrochemically generated hypervalent iodoarenes
The para-selective fluorination reaction of anilides using electrochemically generated hypervalent ArIF2 is reported, with Et3N ⋅ 5HF serving as fluoride source and as supporting electrolyte. This electrochemical reaction is characterized by a simple set-up, easy scalability and affords a broad variety of fluorinated anilides from easily accessible anilides in good yields up to 86 %
Predictive value of CA 125 and CA 72-4 in ovarian borderline tumors
Background: The aim of this study was to assess the prognostic value of cancer antigen (CA) 125 and CA 72-4 in patients with ovarian borderline tumor (BOT). Methods: All women diagnosed and treated for BOT at our institution between 1981 and 2008 were included into this retrospective study (n=101). Preoperatively collected serum samples were analyzed for CA 125 (Architect, Abbott and Elecsys, Roche) and CA 724 (Elecsys, Roche) with reference to clinical data and compared to healthy women (n=109) and ovarian cancer patients (n=130). Results: With a median of 34.7 U/mL (range 18.1-385.0 U/mL) for CA 125 and 2.3 U/mL (range 0.2-277.0 U/mL) for CA 72-4, serum tumor markers in BOT patients were significantly elevated as compared to healthy women with a median CA 125 of 13.5 U/mL (range 4.0-49.7 U/mL) and median CA 72-4 of 0.8 U/mL (range 0.2-20.6 U/mL). In addition, there was a significant difference compared with ovarian cancer patients who showed a median CA 125 of 401.5 U/mL (range 12.5-35,813 U/mL), but no difference was observed for CA 72-4 (median 3.9 U/mL, range 0.3-10,068 U/mL). Patients with a pT1a tumor stage had significantly lower values of CA 125 but not of CA 72-4 compared with individuals with higher tumor stages (median CA 125 29.9 U/mL for pT1a vs. 50.9 U/mL for) pT1a; p=0.014). There was a trend for increased concentrations of CA 125 but not of CA 72-4 in the presence of ascites, endometriosis or peritoneal implants at primary diagnosis. With respect to the prognostic value of CA 125 or CA 72-4, CA 125 was significantly higher at primary diagnosis in patients who later developed recurrence (251.0 U/mL vs. 34.65 U/mL, p=0.012). Conclusions: Serum CA 125 and CA 72-4 concentrations in BOT patients differ from healthy controls and patients with ovarian cancer. CA 125, but not CA 724, at primary diagnosis correlates with tumor stage and tends to be increased in the presence of ascites, endometriosis or peritoneal implants. Moreover, CA 125 at primary diagnosis appears to have prognostic value for recurrence. Clin Chem Lab Med 2009; 47:537-42
Retroviral enhancer detection insertions in zebrafish combined with comparative genomics reveal genomic regulatory blocks - a fundamental feature of vertebrate genomes
A large-scale enhancer detection screen was performed in the zebrafish using a retroviral vector carrying a basal promoter and a fluorescent protein reporter cassette. Analysis of insertional hotspots uncovered areas around developmental regulatory genes in which an insertion results in the same global expression pattern, irrespective of exact position. These areas coincide with vertebrate chromosomal segments containing identical gene order; a phenomenon known as conserved synteny and thought to be a vestige of evolution. Genomic comparative studies have found large numbers of highly conserved noncoding elements (HCNEs) spanning these and other loci. HCNEs are thought to act as transcriptional enhancers based on the finding that many of those that have been tested direct tissue specific expression in transient or transgenic assays. Although gene order in hox and other gene clusters has long been known to be conserved because of shared regulatory sequences or overlapping transcriptional units, the chromosomal areas found through insertional hotspots contain only one or a few developmental regulatory genes as well as phylogenetically unrelated genes. We have termed these regions genomic regulatory blocks (GRBs), and show that they underlie the phenomenon of conserved synteny through all sequenced vertebrate genomes. After teleost whole genome duplication, a subset of GRBs were retained in two copies, underwent degenerative changes compared with tetrapod loci that exist as single copy, and that therefore can be viewed as representing the ancestral form. We discuss these findings in light of evolution of vertebrate chromosomal architecture and the identification of human disease mutations
Visible-to-telecom quantum frequency conversion of light from a single quantum emitter
Quantum frequency conversion (QFC), a nonlinear optical process in which the
frequency of a quantum light field is altered while conserving its
non-classical correlations, was first demonstrated 20 years ago. Meanwhile, it
is considered an essential tool for the implementation of quantum repeaters
since it allows for interfacing quantum memories with telecom-wavelength
photons as quantum information carriers. Here we demonstrate efficient (>30%)
QFC of visible single photons (711 nm) emitted by a quantum dot (QD) to a
telecom wavelength (1,313 nm). Analysis of the first and second-order coherence
before and after wavelength conversion clearly proves that important
properties, such as the coherence time and photon antibunching, are fully
conserved during the frequency translation process. Our findings underline the
great potential of single photon sources on demand in combination with QFC as a
promising technique for quantum repeater schemes.Comment: 11 pages, 4 figure
New Approach to Silver Halide Photography Using Radical Cation Chemistry
A new mechanism for spectral sensitization of silver halide is described, which can potentially double the sensitivity of photographic emulsions. The photooxidized sensitizing dye is trapped using an organic donor molecule, which fragments to form a cation and a reducing radical, which injects an electron into the conduction band of the silver halide. In this way, two conduction-band electrons can be produced for each absorbed photon
Off-label use in germany - a current appraisal of gynaecologic university departments
<p>Abstract</p> <p>Objective</p> <p>The off-label use, referring to the applicability of pharmaceutical drugs beyond the submitted and from the Federal Institute for Drugs and Medical Devices (BfArM, Bundesamt für Arzneimittel und Medizinprodukte) certified and approved administration, is the subject of controversial discussions. the application can be considered in case of severe illness - if no therapeutic alternatives are available - or it exists as a founded perspective for achieving therapeutic success.</p> <p>Methods</p> <p>A latitudinal study for evaluating the application of off-label use supplements was performed at 43 German university and academic teaching hospitals. Five doctors at each hospital applied off-label pharmaceutical drugs and were called upon to share their personal experience to the application of those medications.</p> <p>Results</p> <p>75 (35%) questionnaires were returned out of 22 (51%) medical centres with 215 contacted physicians. Off-label use was common for 65 (91%) of the physicians. Only 9% of them obviate the application of off-label drugs. About a half of the medication is related to application in obstetrics (54%) and in most cases on an every day basis. Uterotonics were the most commonly used off-label medications (34%). The main part of information about off-label use is obtained from personal information of colleagues (66%) and personal experience (58%). 34% of physicians think that off label use is risky. Interestingly, the view about off label use of medication varies considerably among physicians from various hospitals.</p> <p>Conclusions</p> <p>The application of off-label pharmaceutical drugs in Germany seems to be a well established practice. More than 90% of participators of our trial use at least one medication outside the administration. This includes particularly prostaglandins, anti-hyper-tonic therapeutics and chemotherapeutics.</p
Systematic human/zebrafish comparative identification of cis-regulatory activity around vertebrate developmental transcription factor genes
AbstractPan-vertebrate developmental cis-regulatory elements are discernible as highly conserved noncoding elements (HCNEs) and are often dispersed over large areas around the pleiotropic genes whose expression they control. On the loci of two developmental transcription factor genes, SOX3 and PAX6, we demonstrate that HCNEs conserved between human and zebrafish can be systematically and reliably tested for their regulatory function in multiple stable transgenes in zebrafish, and their genomic reach estimated with confidence using synteny conservation and HCNE density along these loci. HCNEs of both human and zebrafish function as specific developmental enhancers in zebrafish. We show that human HCNEs result in expression patterns in zebrafish equivalent to those in mouse, establishing zebrafish as a suitable model for large-scale testing of human developmental enhancers. Orthologous human and zebrafish enhancers underwent functional evolution within their sequence and often directed related but non-identical expression patterns. Despite an evolutionary distance of 450 million years, one pax6 HCNE drove expression in identical areas when comparing zebrafish vs. human HCNEs. HCNEs from the same area often drive overlapping patterns, suggesting that multiple regulatory inputs are required to achieve robust and precise complex expression patterns exhibited by developmental genes
Fruit shape diversity in the Brassicaceae is generated by varying patterns of anisotropy
Fruits exhibit a vast array of different 3D shapes, from simple spheres and cylinders to more complex curved forms; however, the mechanism by which growth is oriented and coordinated to generate this diversity of forms is unclear. Here, we compare the growth patterns and orientations for two very different fruit shapes in the Brassicaceae: the heart-shaped Capsella rubella silicle and the near-cylindrical Arabidopsis thaliana silique. We show, through a combination of clonal and morphological analyses, that the different shapes involve different patterns of anisotropic growth during three phases. These experimental data can be accounted for by a tissue-level model in which specified growth rates vary in space and time and are oriented by a proximodistal polarity field. The resulting tissue conflicts lead to deformation of the tissue as it grows. The model allows us to identify tissue-specific and temporally specific activities required to obtain the individual shapes. One such activity may be provided by the valve-identity gene FRUITFULL, which we show through comparative mutant analysis to modulate fruit shape during post-fertilisation growth of both species. Simple modulations of the model presented here can also broadly account for the variety of shapes in other Brassicaceae species, thus providing a simplified framework for fruit development and shape diversity
Robot life: simulation and participation in the study of evolution and social behavior.
This paper explores the case of using robots to simulate evolution, in particular the case of Hamilton's Law. The uses of robots raises several questions that this paper seeks to address. The first concerns the role of the robots in biological research: do they simulate something (life, evolution, sociality) or do they participate in something? The second question concerns the physicality of the robots: what difference does embodiment make to the role of the robot in these experiments. Thirdly, how do life, embodiment and social behavior relate in contemporary biology and why is it possible for robots to illuminate this relation? These questions are provoked by a strange similarity that has not been noted before: between the problem of simulation in philosophy of science, and Deleuze's reading of Plato on the relationship of ideas, copies and simulacra
Comparative pharmacodynamics of four different carbapenems in combination with polymyxin B against carbapenem-resistant Acinetobacter baumannii
The objective of this study was to determine the comparative pharmacodynamics of four different carbapenems in combination with polymyxin B (PMB) against carbapenem-resistant Acinetobacter baumannii isolates using time–kill experiments at two different inocula. Two A. baumannii strains (03-149-1 and N16870) with carbapenem minimum inhibitory concentrations (MICs) ranging from 8 to 64 mg/L were investigated in 48-h time–kill experiments using starting inocula of 106 CFU/mL and 108 CFU/mL. Concentration arrays of ertapenem, doripenem, meropenem and imipenem at 0.25×, 0.5×, 1×, 1.5× and 2× published maximum serum concentration (Cmax) values (Cmax concentrations of 12, 21, 48 and 60 mg/L, respectively) were investigated in the presence of 1.5 mg/L PMB. Use of carbapenems without PMB resulted in drastic re-growth. All carbapenem combinations were able to achieve a ≥3 log10 CFU/mL reduction by 4 h against both strains at 106 CFU/mL, whereas maximum reductions against strain 03-149-1 at 108 CFU/mL were 1.0, 3.2, 2.2 and 3.3 log10 CFU/mL for ertapenem, doripenem, meropenem and imipenem, respectively. None of the combinations were capable of reducing 108 CFU/mL of N16870 by ≥2 log10 CFU/mL. Ertapenem combinations consistently displayed the least activity, whereas doripenem, meropenem and imipenem combinations had similar activities that were poorly predicted by carbapenem MICs. As doripenem, meropenem, or imipenem displayed similar pharmacodyanmics in combination, the decision of which carbapenem to use in combination with PMB may be based on toxicodynamic profiles if drastic discordance in MICs is not present
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