A highly sensitive HPLC method was developed for the determination of xenoestrogenic compound, bisphenol A (BPA) in human breast milk samples. After a two-step liquid-liquid extraction, BPA was derivatized with fluorescent labeling reagent, 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoyl chloride (DIB-Cl). The excess fluorescent reagent could be removed effectively using a column-switching system. The separation of DIB-BPA from endogenous materials in milk was carried out on two C(18) columns and fluorescence intensity was monitored at 475 nm with the excitation of 350 nm. A good linearity (r = 0.994) was observed of BPA in the concentration range of 0.2-5.0 ng mL(-1) in breast milk, and the detection limit was 0.11 ng mL(-1) at a signal-to-noise ratio of 3. Intra- and inter-day precision (RSD, %) were less than 8.7 and 10.4, respectively. Twenty-three breast milk samples of healthy lactating women were analyzed for the BPA concentration; the mean value was 0.61 +/- 0.20 ng mL(-1), with no correlation to the lipid content of milk samples.

No abstract

No abstract

No abstract

BACKGROUND Analysis of circulating immune complexes (CICs) produced during an immune response may be useful in elucidating some aspects of this process. Identification of antigens incorporated into CICs provides information that may be helpful in developing diagnostic and treatment strategies for autoimmune diseases, infection, cancer, and transplantation therapy, and such information might be more relevant than information on free antigens. Because CICs may contain many antigens, comprehensive identification and profiling of such antigens is more effective than immunoblotting detection. METHODS We developed a novel proteomic strategy (immune complexome analysis) in which immune complexes (ICs) are separated from serum, digested directly with trypsin, and then subjected to nano-liquid chromatography–tandem mass spectrometry for identifying and profiling antigens in CICs. We applied this strategy to the analysis of CICs in 21 rheumatoid arthritis (RA) patients. Serum samples from 13 healthy donors and 8 osteoarthritis patients were used as controls. RESULTS CICs containing thrombospondin-1 (TSP-1) and platelet factor 4 (PF4) were found in the serum of 81% and 52% of RA patients, respectively, and in none of the controls. CONCLUSIONS The ICs in the serum of a majority of the RA patients contained TSP-1 or PF4, and these ICs may have potential as alternative biomarkers. Our technique for immune complexome analysis uses routine clinical samples, simple protocols, and widely available equipment. This method may be generally applicable to the study of the relationship between CICs and certain diseases associated with the immune response in animals and humans.

A sensitive column switching HPLC-fluorescence detection for determination of bisphenol A (BPA) in rat brain by coupling with microdialysis was developed. A microdialysis probe was inserted into the hypothalamus of rat brain and an artificial cerebrospinal fluid was used for perfusion. BPA in brain dialysate was subjected to a fluorescent derivatization with 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoyl chloride (DIB-Cl), and the excess reagent was removed by a column-switching technique. Separation was carried out on two ODS semimicro-columns with the mobile phase of acetonitrile-H(2)O-methanol-tetrahydrofuran (55:10:35:2.5, v/v) and acetonitrile-0.1 M acetate buffer (pH 3.0)-methanol (35:10:55, v/v) at a flow rate of 0.10 and 0.15 mL/min for a precolumn and a separation column, respectively. Fluorescence intensity was monitored at 475 nm with excitation of 350 nm. BPA could be sensitively detected at 0.3 ppb in 60 micro L brain microdialysate at a signal-to-noise ratio of 3. By the proposed method, concentrations of BPA in rat brain and plasma were monitored for 8 h after single i.v. or oral administration. It is proved that BPA is capable of penetrating the blood-brain barrier. The ratio of the area under the concentration-time curve of BPA in rat brain to that in blood was estimated to be about 3.0-3.8%.

Synchronized bio-distribution of combination therapies has several merits such as synergistic effects and reduced side-effects. Co-delivery of a protein and small molecule drug using a single nanocarrier is challenging because they possess totally different characteristics. Herein, we report the development of sophisticated nanoparticles composed of lipids, calcium carbonate and RGD peptide ligands for the co-delivery of a protein and small molecule drug combination via a simple preparation method. A 'one-step' ethanol injection method was employed to prepare the highly organized nanoparticles. The nanoparticles exhibited a spherical shape with ca. 130 nm diameter, and clearly had an integrated lipid layer covering the periphery. As a ligand, an RGDmodified lipid was post-inserted into the nanoparticles, which was important to overcome the 'PEG dilemma'. The pH-sensitivity of the targeted nanoparticles contributed to the efficient intracellular co-delivery of a protein and drug combination in Colon26 tumor cells, and noticeably improved their accumulation in the tumor region of xenograft mice. Synchronized bio-distribution of the protein and drug was achieved, which was the foundation for the synergistic effects of the combination. The targeting capability of the nanoparticles along with their pH-sensitive drug release and the synchronized bio-distribution of their cargos led to the significant antitumor activity of the SOD and paclitaxel combination in mice. This study provides novel information for the design and preparation of functionalized nanoparticles for the delivery of a protein/drug combination in vivo.

No abstract