A selective adsorption-based separation of low-mass molecules from biological samples towards high-throughput mass spectrometry analysis in a single drop of human whole blood.

In this work, a newly designed multifunctional adsorbent material, octadecyl-modified ordered mesoporous carbon (C18-CMK-8), was synthesized and employed for simultaneous analysis of multiple small molecules by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The C18-CMK-8 was facilely prepared by one-step chemical binding of octadecyltrimethoxysilane to an ordered mesoporous carbon CMK-8. The nanosized pore structure of C18-CMK-8 can selectively enrich low-mass molecules while excluding interferences from large molecules in whole blood; meanwhile, the C18 chain can greatly enhance the affinity for a wide range of small molecules. Then, the C18-CMK-8-based solid-phase extraction (SPE) combined with MALDI-TOF MS measurement was applied in rapid and high-throughput screening of six doping agents (triamterene, trenbolone, testosterone, methyltestosterone, clenbuterol, and strychnine)) in single-drop human whole blood samples. The method showed high analytical sensitivity (detection limit 0.05-0.1 ng mL-1), good recoveries (67.2-114.3%), minimal sample requirement (∼20 µL), and robust anti-interference ability. With distinct advantages such as high throughput, rapidness, minimal sample requirement, and high sensitivity, this study not only offers a versatile enrichment material for complex sample preparation, but also demonstrates a promising tool for minimal whole blood analysis.

Synthesis and biological evaluation of silylated mixed-ligand 99mTc complexes with the [PNS/S] donor atom set.

New oxotechnetium complexes of general formula [99mTc(O)(PNS)(S(CH2)nOSiR3)] (4-6) were synthesized by direct reduction of [99mTcO4]- with stannous chloride, in the presence of the tridentate heterofunctionalized phosphine H2PNS and of the monodentate silylated thiols [HS(CH2)nOSiR3] (n = 2, R = Ph (1); n = 3, R = Ph (2); n = 3, R = Et (3)). The mixed-ligand rhenium and technetium complexes of general formula [M(O)(PNS)(S(CH2)nOH)] (n = 2: M = 99mTc, (7), M = Re, (7a); n = 3: M = 99mTc, (8), M = Re, (8a)) were also prepared. All the 99mTc complexes were obtained with high radiochemical purity (> 95%), after purification by HPLC, and were characterized by comparison of their HPLC profiles with the ones obtained for the corresponding Re compounds. The silylated compounds 4-6 are stable in phosphate saline buffer (PBS) pH 7.4, rat plasma, human serum and whole blood, and do not bind to plasmatic proteins, and also do not challenge with glutathione. The biological behavior of [99mTc(O)(PNS)(S(CH2)nOH)] (7, 8) and [99mTc(O)(PNS)(S(CH2)nOSiR3)] (4-6) was studied. The effect of the pH on the cleavage of the O-Si bond in complexes 4-6 was also evaluated.

Surface-localized release of nitric oxide via sol-gel chemistry.

The release of nitric oxide (NO) from polymers has proven to be highly effective at inhibiting platelet adhesion and thus enhancing the blood compatibility of medical implants. Micropatterning techniques were used to design surfaces that release NO while preserving the underlying substrate for other applications (e.g., sensors). Micropatterned NO-releasing substrates based on aminosilane-containing methyltrimethoxysilane sol-gels were prepared and characterized in terms of stability, NO surface flux, and resistance to in vitro platelet adhesion. We have found that surface-localized NO release from substrates modified with sol-gel micropatterns exhibit enhanced blood compatibility relative to controls.

Silicon bioavailability studies in young rapidly growing rats and turkeys fed semipurified diets: a comparative study.

Two experiments were conducted using completely randomized designs to study the bioavailability of Si from three sources to growing rats and turkeys fed semipurified diets. The basal diets were dextrose-egg albumin for rats and dextrose-casein for turkeys. The Si sources were tetraethylorthosilicate (TES), sodium silicate (NaSil), and sodium zeolite A (NaZA). Rats and turkeys were supplemented at 500 and 270 ppm Si, respectively, from each source. A control group of unsupplemented rats and turkeys was included in each experiment. In general, irrespective of Si source, Si supplementation slowed (p < 0.05 or p < 0.01) growth rates in both rats and turkeys. Although dietary Si supplementation reduced (p < 0.05) plasma Mg levels and liver Zn concentrations in rats, it increased (p < 0.05) plasma P and reduced (p < 0.05) plasma Cu levels in turkeys. Rats on TES had significantly slower (p < 0.05 or p < 0.01) growth rates (5-10%) than those on NaSil or NaZA. In rats, NaZA and TES reduced (p < 0.05) hemoglobin concentrations and plasma Zn, respectively. However, plasma Mg levels were higher (p < 0.05) in TES than NaSil- or NaZA-fed rats. The source of the dietary Si did not affect (p < 0.05) the organ weights of rats and their mineral concentrations. Turkeys on TES diets grew at a significantly faster (p < 0.05) rate (15%) than those on NaSil or NaZA diets during the first 2 wk of experimentation. However, after 4 wk, there were no significant(p > 0.05) differences in growth between the Si sources. In turkeys, NaZA increased (p < 0.05) hematocrit levels and plasma Mg levels. Turkeys on NaZA diets had larger (p < 0.05) hearts and livers than those on NaSil but not TES. Liver Mn content was higher (p < 0.05) in turkeys on NaSil than TES or NaZA. Heart Zn was lower (p < 0.05) in turkeys on NaSil than TES, but not NaZA.

High-performance liquid chromatographic method for the determination of RGH-5002 in human, rabbit and rat plasma.

A sensitive, accurate and reproducible high performance liquid chromatography (HPLC) procedure for the analysis of RGH-5002 in biological fluids was developed. After a single step liquid-liquid extraction at pH 9 using n-hexane, RGH-5002 and internal standard were eluted from a Hypersil Si column with 5 mM ammonium acetate-methanol-acetonitrile (0.5:45:50 v/v/v) at 28 degrees C. The method could accurately detect 5 ng ml-1 of RGH-5002.