CD80 and CD86 knockdown in dendritic cells regulates Th1/Th2 cytokine production in asthmatic mice.

Dendritic cells (DCs) are associated with the activation and differentiation of T helper (Th) cells. Cluster of differentiation (CD)80 and CD86, the co-stimulatory molecules highly expressed in DCs, have are prominent in promoting the differentiation of Th cells toward Th2 cells. However, little is known about the effect of CD80 and CD86 knockdown on Th1/Th2 cytokine production in mature DCs (mDCs). The aim of the present study was to investigate whether small-interfering RNA (siRNA) could suppress the surface expression of CD80 and CD86 in mDCs. The effects of CD80 and CD86 knockdown in mDCs on Th1/Th2 cytokine expression were examined using an asthmatic murine model. DCs were isolated, separated and cultured in vitro. Flow cytometry was used to examine the expression of CD11c, CD80 and CD86 on the DCs. The DCs were transfected with CD80- and CD86-specific siRNA, while non-siRNA and negative siRNA controls were also designed. Then, the mRNA and protein expression levels of CD80 and CD86 were determined by reverse transcription-quantitative polymerase chain reaction and flow cytometry, respectively. The levels of interferon (IFN)-γ and interleukin (IL)-4 produced by T cells co-cultured with mDCs were measured by enzyme-linked immunosorbent assay. Substantial downregulation of CD80 and CD86 mRNA and protein levels were observed in the mDCs following transfection with siRNA. The level of IFN-γ produced by T cells co-cultured with mDCs was significantly increased in the siRNA group, while IL-4 production was significantly decreased. These results show that specific targeting of CD80 and CD86 with siRNA is able to suppress CD80/CD86 expression and consequently regulate Th1/Th2 cytokine levels by increasing IFN-γ production and decreasing IL-4 levels in an asthmatic murine model.

[Interaction between ambroxol hydrochloride and human serum albumin studied by spectroscopic and molecular modeling methods].

In the present paper, the interaction between ambroxol hydrochloride (ABX) and human serum albumin (HSA) was studied under simulative physiological condition by spectroscopy and molecular modeling method. Stern-Volmer curvers at different temperatures and UV-Vis absorption spectroscopy showed that ABX quenched the fluorescence of HSA mainly through dynamic quenching mode. On the basis of the thermodynamic data, the main binding force between them is hydrophobic interaction. According to the theory of Forster non-radiation energy transfer, the binding distance between the donor and the acceptor was 3.01 nm. The effect of ABX on the conformation of HSA was analyzed by the synchronous and three-dimensional fluorescence spectroscopy. Furthermore, using the molecular modeling method, the interaction between them was predicted from molecular angle: ABX might locate in the subdomain III A of HSA.

Spectrofluorimetric determination of pentachlorophenol based on its inhibitory effect on the redox reaction between hydroxyl radicals and fluorescent dye rhodamine B.

Hydroxyl radicals that is generated by Fenton reagent reacts with rhodamine B, which makes the fluorescence quenching of rhodamine B. However, there is an inhibitory effect of pentachlorophenol on the reaction. Based on this observation, an inhibitory fluorimetric method is reported for the determination of trace pentachlorophenol. The fluorescent inhibition of rhodamine B is measured by fix-time method. On the optimum conditions of experimentation, the detection limit for pentachlorophenol is 3.0 ng/ml and the linear range of the determination is 4.0-240 ng/ml. Combined with the samples treating with ion exchange resins and XDA-1 absorption resin, the method has been used for the determination of pentachlorophenol in synthetic samples and natural water samples with satisfactory results. We have also discussed the possible mechanism of the reaction.

[Spectrometric study on the interaction of doxepin hydrochloride and fast green and its application].

The characteristics of resonance light scattering and absorption spectra of doxepin hydrochloride with fast green were investigated, and a new analytical method for doxepin hydrochloride was described. In the buffer solution of pH 4.0, doxepin hydrochloride can strengthen the signal of resonance light scattering of fast green. The effective factors, including the order of addition of the reagents, acidity and kinds of the buffers, and concentration of fast green were investigated. Under the optimum conditions, the scattering peaks of the system are at 344 and 486 nm, while the maximum is at 344 nm. The enhanced intensity of RLS is proportional to the concentration of doxepin hydrochloried in the range of 8.75 x 10(-3)-4.88 x 10(-2) mg x mL(-1). The detection limit for doxepin hydrochloried is 1.72 x 10(-5) mg x mL(-1). The relative standard deviation obtained from eleven determinations for a 0.025 mg x mL(-1) standard solution of doxepin hydrochloried is 1.4%. The method was applied to the determination of doxepin hydrochloric in pharmaceutical preparations. The results were compared with those obtained by the reference method, and t-test showed no significant difference between the two methods.

[Highly sensitive fluorescent reaction of acridine red with chromium (VI) and its application].

A simple and highly sensitive fluorimetric method for the determination of Cr(VI) was developed in the present paper. The method is based on the fluorescence enhancement of acridine red with Cr(VI) in the sulfuric acid medium. The effects of some experimental conditions on the determination of Cr(VI) were investigated in detail. The detection limit for Cr(VI) is 0.6 microg x L(-1), and the linear range of the determination is 2.0-32 microg x L(-1). The relative standard deviation of 11 replicate measurements is less than 2.0%. The proposed method has been successfully used to determine Cr(VI) in electroplating solution, waste chromic acid mixture, and alloy steel samples. The results obtained were compared with the certified values of Cr(VI) in standard samples and those provided by 1, 5-diphenylcarbazide method with satisfaction.

[Studies on the interaction between thionine and deoxyribo-nucleic acid by ethidium bromide probe].

The interaction between thionine and deoxyribonucleic acid was studied with ethidium bromide probe in Tris-HCl buffer solution at pH 7.4 by fluorescence spectra, electronic absorption spectra, and resonance light scattering spectra. From the obtained results, it was found obviously that the planar structure of thionine can be intercalated into the stacked base pairs of DNA, which is the major controlling factor. The binding constant was found to be 1.0 x 10(5) L x mol(-1).

[Microdetermination of proteins with Titan yellow by the resonance light scattering method].

A resonance light scattering method for the determination of trace proteins was developed. In the presence of Triton X-100, proteins reacted with Titan yellow to form a combination product, resulting a significant enhancement of resonance light scattering (RLS). The deltaI(RLS) was directly proportional to the concentration of protein in the range of 0.03-0.9 microg x mL(-1), with the detection limit 17.7 ng x mL(-1) for BSA. This method was applied to the determination of the proteins in synthetic and human serum samples, and compared to the CBB method, with satisfactory results.

[Spectral study and determination of metoclopramide and procaine hydrochloride by sequential injection analysis].

A sequential injection spectrophotometric method is proposed for the determination of metoclopramide or procaine hydrochloride, based on the reactions of metoclopramide and procaine hydrochloride with cerium(IV) in sulfuric acid medium. Red intermediate products were observed and were found unstable so that their analytical use is only possible by sequential injection technology. For metoclopramide, the detection limit is 6.5 microg x mL(-1), and the linear range of determination is 9.7-116.6 microg x mL(-1) with a sampling frequency of 45 h(-1). For procaine hydrochloride, the detection limit is 7.4 microg x mL(-1), and the linear range of the determination is 10.0-130.0 microg x mL(-1) with a sampling frequency of 45 h(-1). The method has been applied to the determination of metoclopramide and procaine hydrochloride in tablets and injections with satisfactory results as compared with standard method.

[Inhibitory kinetic fluorimetric determination of trace aniline].

An inhibitory kinetic fluorimetric method is reported for the determination of trace aniline. The proposed method is based on the inhibitory effect of aniline on the reaction of potassium periodate oxidation of rhodamine 6G in phosphoric acid medium. The detection limit is 7.2 ng x mL(-1), the linear range of the determination is 0.010-0.183 microg x mL(-1). This method has been applied to the determination of trace aniline in phenolic tubes and water samples with satisfactory results.

[Determination of deoxyribonucleic acids based on the enhanced effect of resonance light scattering of malachite green sensitized by cetyltrimethylammonium bromide].

A resonance light scattering (RLS) enhancement method was reported for the determination of deoxyribonucleic acids. The proposed method was based on the enhanced effect of deoxyribonucleic acid on the resonance light scattering of malachite green (MG) sensitized by cetyltrimethylammonium bromide (CTMAB). Alkaline medium was necessary for the experiment. Under optimal conditions, the linear ranges for both calf thymus DNA (ctDNA) and fish sperm DNA (fsDNA) were 0-1.5 microg x mL(-1), the detection limits were 0.05 microg x mL(-1) for ctDNA and 0.03 microg x mL(-1) for fsDNA. The measurement can be made on normal spectrofluorimeter. Mechanic studies show that MG probably aggregates on the molecular surface of single-chained DNA, and then interacts on CTMAB to form large particles, which produce strong RLS. This method was successfully applied to the determination of DNA in synthetic samples.

[Study on the kinetic fluorimetric determination of tannins in tea].

A simple and highly sensitive kinetic fluorimetric method is proposed for the determination of trace tannins, based on the activation of tannins on the oxidation of pyronine Y by hydrogen peroxide catalyzed by Cu(II) ion. The effects of some experimental conditions were investigated and discussed in detail. The fixed reaction time procedure was used to determine the fluorescence intensity of the system. The calibration curve of tannin was linear in the range of 0.06-0.96 mg.L-1, and the detection limit for tannin was 0.032 mg.L-1. The relative standard deviation for the measurement of 0.32 mg.L-1 tannin (n = 11) was 2.3%. The proposed method has been successfully applied to the determination of tannins in tea. The results obtained were compared with those provided by the Folin-Ciocalteu method.