Search results for "Reagent"
showing 9 items of 699 documents
Zein as biodegradable material for effective delivery of alkaline phosphatase and substrates in biokits and biosensors
2016
A biodegradable material, zein, is proposed as a reagent delivery platform for biokits and biosensors based on alkaline phosphatase (ALP) activity/inhibition in the presence of phosphatase substrates. The immobilization and release of both the substrate and/or the active ALP, in a biodegradable and low-cost material such as zein, a prolamin from maize, and in combination with glycerol as plasticizer have been investigated. Three zein-based devices are proposed for several applications: (1) inorganic phosphorus estimation in water of different sources (river, lake, coastal water and tap water) with a detection limit of 0.2mg/L - compared to at least 1mg/L required by legislation, (2) estimat…
Modular Solid-Phase Synthesis of Antiprotozoal Barnesin Derivatives
2020
Here, we applied and optimized a solid support (SP)-based Horner-Wadsworth-Emmons reagent to prepare SP-bound vinylogous amino acids. Subsequent SP-based peptide synthesis, global deprotection, and chemical modifications yielded 14 lipodipeptides carrying vinylogous amino acids, including the natural product barnesin A (1). Biological evaluation revealed that several synthesized derivatives show micromolar to nanomolar inhibitory activity against papain-like cysteine proteases, human cathepsin L, and rhodesain.
Monoclonal antibody 3H8: A useful tool in the diagnosis of candidiasis
1999
In a previous series of experiments six mAbs were obtained against cell wall extracts of Candida albicans ATCC 26555. After several studies only one of them, designated 3H8, has been used to produce a commercial kit for the rapid diagnosis of candidiasis, Bichro-latex albicans (Fomouze Diagnostics). The present study involved the generation and characterization of this mAb as an immunoglobulin G1 which recognizes mannoproteins of high molecular mass present in the C. albicans cell wall. ELISA assays showed that the presence of the epitope recognized by mAb 3H8 was similar in both yeast and mycelial cell walls of C. albicans, in contrast to the epitope for mAb 1B12, which is mainly expressed…
Dithiothreitol prevents age-associated decrease in oocyte/conceptus viability in vitro.
1998
The present study was designed to ascertain whether the negative effects on reproductive potential of post-ovulatory ageing in vitro of oocytes can be prevented by antioxidant therapy. Mouse metaphase II (MII) oocytes were aged in vitro for 12 h prior to insemination in the presence of varying concentrations of L-ascorbic acid, 6-methoxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox), L-cystine dihydrochloride, ethylenediaminetetraacetic acid (EDTA), beta-mercaptoethanol and DL-dithiothreitol (DTT). In-vitro ageing of oocytes was associated with lower fertilization rate, higher proportion of concepti exhibiting cellular fragmentation at 24 h post-insemination and lower percentage of…
Cost-effectiveness of screening for colorectal cancer in France using a guaiac test versus an immunochemical test
2010
Objectives: The aim of this study was to compare the cost and the effectiveness of two biennial fecal occult blood screening tests for colorectal cancer: a guaiac nonrehydrated test (G-FOBT) and an immunochemical test (I-FOBT) with the absence of screening.Methods: A Markov model was developed to compare these strategies in a general population of subjects aged 50 to 74 over a 20-year period.Results: Compared with the absence of screening, G-FOBT and I-FOBT were associated with a decrease in colorectal cancer mortality of 17.4 percent and 25.2 percent, respectively. With regard to cost-effectiveness, expressed as cost per life-year gained, I-FOBT was the most effective and most costly alter…
Screening for colorectal cancer with immunochemical faecal occult blood tests.
2012
Population-based studies have shown that guaiac faecal occult blood testing followed by colonoscopy in case of positivity can reduce colorectal cancer mortality. However these tests have been criticised for their fairly low sensitivity. For this reason attention has been given to alternative tests. The aim of this paper is to review the evidence for screening for colorectal cancer using qualitative immunochemical faecal occult blood tests. For the complete range of tested cut-off values, immunochemical faecal occult blood tests lead to higher diagnostic yield, improved sensitivity and greater participation. The optimal number of samples and the optimal cut-off value has to suit local resour…
Modulation of central corneal thickness by various riboflavin eyedrop compositions in porcine corneas
2012
Purpose To evaluate the modulatory effect of various riboflavin 0.1% and 0.2% compositions on the central corneal thickness (CCT) in fresh porcine corneas. Setting Department of Ophthalmology, Johannes Gutenberg University of Mainz, Mainz, Germany. Design Experimental study. Methods The CCT in freshly enucleated porcine globes was measured by ultrasound pachymetry before and after (if applicable) deepithelialization and every 10 minutes thereafter during 120 minutes of eyedrop application. In Groups 1 and 2 (controls), no eyedrops were applied. In Groups 3 and 4, isotonic riboflavin eyedrops were used. In Groups 5 to 9, hypotonic riboflavin eyedrops were given. In Groups 10 and 11, preparat…
P-C Cross-Coupling Onto Enamides: Versatile Synthesis of α-Enamido Phosphane Derivatives
2012
We report herein the Pd-catalyzed P–C cross-coupling reac- tion between enol phosphates and secondary phosphane–bor- ane complexes or phosphane oxides. The reaction was per- formed under mild conditions, owing to Pd activation of the P–H bonds of the phosphane–boranes (or phosphane oxides) and to the powerful enol phosphate coupling reagents. New useful chiral and achiral α - β -alkenylphosphane derivatives bearing an amido group in the α -position to the P center were obtained in yields up to 70 %.
Structural Motifs of Alkali Metal Superbases in Non‐coordinating Solvents
2020
Abstract Lochmann–Schlosser superbases (LSB) are a standard reagent in synthetic chemistry to achieve an exchange of a proton on an organic framework with an alkali metal cation, which in turn can be replaced by a wide range of electrophilic groups. In standard examples, the deprotonating reagent consists of an equimolar mixture of n‐butyllithium and potassium t‐butoxide. However, the nature of the reactive species could not be pinned down either for this composition or for similar mixtures with comparable high reactivity. Despite the poor solubility and the fierce reactivity, some insights into this mixture were achieved by some indirect results, comparison with chemically related systems,…