Effects of immobilization on a FRET immunosensor for the detection of myocardial infarction

A novel optical biosensor technique is being developed for the early detection of myocardial infarction by utilizing the distance-dependent chemical transduction method of fluorescence resonance energy transfer (FRET). The FRET process requires two fluorophores termed the donor and the acceptor. When in close proximity, the donor absorbs energy from the excitation source and non-radiatively transfers the energy to the acceptor, which in turn emits fluorescent energy. This distance-dependent property was utilized to detect conformational changes when antibodies combine with their respective antigens. The fluorophores were conjugated to an antibody–Protein A complex and then immobilized via silanization to the distal ends of optical fibers. Three different antibody–Protein A complexes were immobilized: generic IgG, cardiac Troponin T (cTnT), and cardiac Troponin I (cTnI). Results showed that upon the addition of the specific antigens, the antibodies underwent a conformational change, reducing the distance between the FRET fluorophores. The generic IgG responded to 233 nM antigens, whereas the cTnT biosensor had a limit of detection of 75 nM, and the cTnI biosensors had a limit of detection of 94 nM.     

Measurement of adriamycin (doxorubicin) and its metabolites in human plasma using reversed-phase high-performance liquid chromatography and fluorescence detection

We describe a method for measuring adriamycin and its major metabolite, adriamycinol, in plasma, using reversed-phase high-performance liquid chromatography and fluorescence detection. The lower limit of detection is approximately 1 ng/ml for both compounds; within-day coefficients of variation are 3.6% and 4.4% for adriamycin and adriamycinol, respectively. A slight modification of this procedure also allows measurement of aglycone metabolites.     

Alpha-lithiosilanes: III. The Reaction of Vinylalkoxysilanes with Organolithium Reagents

The reaction of two equivalents of vinyldimethylethoxysilane or vinyldimethylmethoxysilane with hydrocarbon soluble alkyllithium reagents; $\text{t}$-BuLi, $\text{s}$-BuLi, or $\text{n}$-BuLi; in hexane at low temperature gives high yields of 1,1-dimethyl-2-alkyl-4-(dimethylalkoxysilyl)silacyclobutanes. With methyl- or phenyllithium substituted vinylsilanes are obtained. The stereochemistry of the silacyclobutanes is assigned on the basis of Si-29 and H-1 NMR. For vinyldimethylethoxysilane the ratio of cis to trans silacyclobutane is about $\text{57}\text{43}$, and is independent of the alkyllithium reagent used. In the reaction of vinyldimethylmethoxysilane with $\text{t}$-BuLi a $\text{sol70}\text{30}$ ratio of the cis and trans silacyclobutane is obtained. A pathway is proposed which is consistent with the stereochemical results and with the products isolated in the reaction run in THF.     

Polycycloalkylene-siloxane polymers: Synthesis and thermal study

Based on dicyclopentadiene and silacyclopentene, two linear polycycloalkylene-siloxane polymer systems have been synthesized and the thermal stability of the raw polymers evaluated by differential scanning calorimetry and thermal gravimetric analysis. The DSC data in nitrogen indicate that both polymer systems have excellent thermal stability. In air, these polymers begin to oxidize at approximately 150°C, with catastrophic oxidation occurring at about 400°C.     

Identification of phenylbutyrylglutamine,a new metabolite of phenylbutyrate metabolism in humans

Phenylbutyrate is used in humans for treating inborn errors of ureagenesis, certain forms of cancer, cystic fibrosis and thalassemia. The known metabolism of phenylbutyrate leads to phenylacetylglutamine, which is excreted in urine. We have identified phenylbutyrylglutamine as a new metabolite of phenylbutyrate in human plasma and urine. We describe the synthesis of phenylbutyrylglutamine and its assay by gas chromatography/mass spectrometry as a tert-butyldimethylsilyl or methyl derivative, using standards of [(2)H(5)]phenylbutyrylglutamine and phenylpropionylglutamine. After administration of phenylbutyrate to normal humans, the cumulative urinary excretion of phenylacetate, phenylbutyrate, phenylacetylglutamine and phenylbutyrylglutamine amounts to about half of the dose of phenylbutyrate. Thus, additional metabolites of phenylbutyrate are yet to be identified.