ANALYSIS OF ETHACRYNIC ACID IN URINE BY HPLC-FLUORESEENCE DETECTOR

A sensitive and selective method has been developed for the detection of free ethacrynic acid in human urine. Using 4-(bromomethyl)-7-methoxycoumarin, ethacrynic acid was transformed into a fluorescent derivative, and was analysed by HPLC-fluorescence detector. The detection limit is 0.1ug/ml urine. The method is suitable for screening ethacrynic acid in doping control and studying its metabolism.     

Long-Term Expression of Human Factor Ⅸ cDNA in Rabbits

In this study, rabbits were used as a model for gene therapy for hemophilia B, Human factor Ⅸ cDNA was transferred to cultured normal rabbit skin fibroblasts (RSF) by a recombinant plasmid (pCMVIX) or retrovirus(XL-IX or N2CMVIX) constructed in our laboratoy. Infected fibroblasts capable of synthesizing and secreting high levels of biologically active human factor Ⅸ protein were selected and embedded in a collagen matrix. The latter was surgically implanted into rabbits as autografts or allografts. Human factor Ⅸ protein was detected in the plasma of all the grafted rabbits, and its expression has been maintained for more than 10 months at the time of writing. In addition, we have improved and simplified the method of implantation from surgically grafting the tissue-like matrix to the injection of the infected cell-collagen mixture subcutaneously. Using the latter method, human factor Ⅸ in rabbits injected with RSF-N2CMVIX reached a peak of 480 ng/ml plasma, and its expression has continued for more     

Effect of the Esters of Gallic Acid on Model and Human Blood Platelet Membranes Studied by Fourier Transform Infrared Spectroscopy

Gallic acid is one of the components of Chinese herbal drug Radix paeoniae used for promoting blood circulation to remove blood stasis. This paper studied the effects of gallic acid and its esters (e.g. ethyl, propyl, isobutyl and butyl gallate) on model and human blood platelet membranes by FTIR which was used for monitoring the physical state of the acyl chain, interfacial and head group region of the membrane lipid bilayer. From the experimental results it can be seen that the gallic acid and its esters have the modifying function on the pure and cholesterol-containing DPPC model membranes, and have the quantity-effective and structural-effective relationships. In addition, it is discovered that these esters have the modifying effect on the structure of human blood platelet membrane and can reverse the effect of ADP. That the effect of the esters of gallic acid counteracts the effect of cholesterol and ADP on human blood platelet perhaps provides a new explanation of the mechanism of Chinese herbal d     

Oxidizing mechanism of podophyllotoxin and its derivatives by sodium persulfate

The oxidizing mechanism of podophyllotoxin and its derivatives by sodium persulfate has been studied by laser flash photolysis and pulse radiolysis. The formation and decay processes of transient species of podophyllotoxin and its derivatives have been observed, and a series of rate constants for the formation and decay of transient species have been determined. It has been found that there is a light (UV) sensitive group on the C-4 of podophyllotoxin and two light (UV) sensitive groups on the C-4 and C-4' of 4'-demethylepipodophyllotoxin.     

Extraction chromatographic study of aluminium(III) and mutual separation of aluminium(III), gallium(III), indium(III) and thallium(III) with N-n-octylaniline

A selective method has been developed for extraction chromatographic studies of aluminium(III) and its separation from several metal ions with a chromatographic column containing N-n-octylaniline (liquid anion exchanger) coated on silanized silica gel as a stationary phase. The aluminium(III) was quantitatively extracted with the 0.065 mol/L N-n-octylaninine from 0.013 to 0.05 mol/L sodium succinate at a flow rate of 1.0 mL/min. The extracted metal ion has been recovered by eluting with 25.0 mL of 0.05 mol/L hydrochloric acid and estimated spectrophotometrically with aurintricarboxylic acid. The effects of the acid concentration, the reagent concentration, the flow rate and the eluting agents have been investigated. The log-log plots of distribution coefficient (KdAl(III)) versus N-n-octylaniline concentrationin 0.005 and 0.007 mol/L sodium succinate gave theslopes 0.5 and 0.7 respectively and showed theprobable composition of theextracted species was 1:1 (metal to amine ratio) and the nature of extracted species is [RR''NH2+ Al succinate2-] org. .The extraction of aluminium(III) was carried out in the presence of various ions to ascertain the tolerance limit of individual ions. Aluminium(III) has been separated from multicomponent mixtures, pharmaceutical samples and synthetic mixtures corresponding to alloys. A scheme for mutual separation of aluminium(III), indium(III), gallium(III) and thallium(III) has been developed by using suitable masking agents. The method is fast, accurate and precise.     

Antitumour Activity of Chitosan Hydrogen Selenites

Selenium is a biologically important element and essential for life1. Selenium deficiency causes severe degenerative disease, such as Kesan cardiomyopathy, and has been implicated in increasing the incidence of human cancer and some chronic ailment as well as ageing. Administration of selenium compounds such as sodium selenite protects animals against carcinogens and markedly reduces the incidence of various neoplasms in human2. Chitosan is one of the most abundant glycans in nature and its…     

Determination of Active Ingredients of Hawthorn by Capillary Electrophoresis with Electrochemical Detection

A method based on capillary electrophoresis with electrochemical detection has been developed for the separa-tion and determination of epicatechin,kaempferol,chlorogenic acid,4-hydroxybenzoic acid,quercetin and proto-catechuic acid in hawthorn for the first time.The effects of working electrode potential,pH and concentration ofrunning buffer,separation voltage and injection time on CE-ED were investigated.Under the optimum conditions,the analytes could be separated in a 60 mmol·L~(-1) borate buffer(pH 8.7)within 21 min.A 300 μm diameter carbondisk electrode has a good response at 0.95 V(vs.SCE)for all analytes.The response was linear over three ordersof magnitude with detection limits(S/N=3)ranging from 3×10~(-8) to 2×10~(-7) g·mL~(-1) for the analytes.The methodhas been successfully applied to the analysis of real sample,with satisfactory results.     

Microwave-assisted Polycondensation of L-2-Hydroxy-3-phenylpropanoic Acid

The attempts to prepare novel biodegradable polymer carriers for drug controlled release systems have been tried in our group1,2. Poly (L-2-hydroxy-3-phenylpropanoic acid) (PLHPPA) can be considered as derivative of poly (lactic acid) (PLA) which has been applied as biomaterials in drug delivery systems, surgical repair and tissue engineering materials3 for its excellent biodegradability and biocompatibility. PLHPPA contains phenyl groups in its structure. It is designed as a hydrophobic…     

Syntheses and Crystal Structures of Two Complexes with 3-（3-Pyridyl）acrylic Acid

1 INTRODUCTION A recent feature in the development and progress of chemical research is the concern for molecular assemblies, ensembles, and all of structural aggre- gates[1]. The self-assembly of transition metal ions and N-containing organic ligands has been proven a popular approach for the construction of supramo- lecular architecture[2～7]. 3-(3-Pyridyl)acrylic acid is an excellent ligand, not only due to its prolific coor- dination sites but also to its potential hydrogen bon- ding…     

Determination of abscisic acid based on the fluorescent quenching of quantum dots

The quenching mechanism of the fluorescence of quantum dots by abscisic acid has been systematically investigated.The quenching constant KSV = 5.1 × 1011 / M was obtained under the optimized condition.On the basis of that,a very sensitive method for the determination of abscisic acid has been developed.The linear equation was F0/F = 0.9309 + 0.5072 C(pmol/L) and its linear range was 0.2-3.0 pmol/L with a correlation coefficient of 0.9939.The limit of detection was 0.09 pmol/L.     

Studies on Polymer Chain Dimension in Solution——Calculation of Osmotic Pressures of Polymer Solutions

A modelr which has been developed to account for the effects of concentration on the chain dimensions of dissolved polymers has been combined with Zimm's statistical mechanical relation for the virial coefficients of dilute suspensions of hard spheres. The osmotic pressures (π/c) of 16 types of polymer/solvent calculated are in quite good accordance with experimental results from dilute to semi-dilute solutions and even concentrated solutions.In this procedure no adjustable parameters are needed except for the number average molecular weight of the sample and its intrinsic viscosity estimated from MarkHouwink coefficients.     

Synthesis of Optical Active 2-Arylpropionic Acids

2-Arylpropionic acid and its derivatives are pharmaceutically and agriculturally useful products1,2, especially, the optical isomer possesses extra higher biological or pharmaceutical activity, for example the antiflammatory agent3 of S-2-(6(-methoxyl- (-naphthyl) propionic acid (Naproxen), the effect of (S)-isomer is 28 times as actives as its R isomer. For the preparation of optically active 2-arylalkanoic acids many different synthetic strategies have been reported, such as, the resolution…     

Trichobitacin-a new ribosome-inactivating protein Ⅰ.The isolation,physicochemical and biological properties of trichobitacin

From the press-residue of the fresh root tuber of Trichosanthes kirilowii Maxim (Cu-curbitaceae),a new ribosome-inactivating protein (RIP),trichobitacin,was isolated.It has the activity of RNA N-glycosidase and can inhibit the growth of human placental trophoblastic cells.Its molecular weight is 27,228 Da (ES-MS) and pI 9.6.It is a single chain basic RIP.Its amino acid composition was determined.It is a new RIP.It consists of 0.7~0.9% galactose and may be a glycoprotein.Its A'-and C-terminal amino acid is Asp and Ala,respectively.Its N-terminal preliminary amino acid sequence has been determined.     

Synthesis, Spectroscopic Properties and Structural Characterization of Tri（o-chlorobenzyl）tin Ester of 4-Pyridinecarboxylic Acid

The tri(2-chlorobenzyl)tin(IV) complex with 4-pyridinylcarboxylate ligand tri(o-chlorobenzyl)tin ester of 4-pyridinecarboxylic acid has been synthesized by the reaction of tri(2-chlorobenzyl)tin(Ⅳ) chloride with 4-pyridinyl carboxylic acid and characterized by elemental analysis, IR and ^1HNMR, and its crystal structure was determined by X-ray single-crystal diffraction.     

Studies on the Chemical Structure of llexolide A

A new tritcrpene glycoside,ilexolidc-A(Ⅰ),exhibiting cardiac activity,has been isolated from the root of ilex publcscens HorJk et Am.(Ⅰ) has been determined as a β-xyloside of iicxolic acid(Ⅱ),(Ⅱ) is also a new triterpenic acid,and its structure has been assigned as 18-dehydro-20-epi-ursolic acid by chemical reactions and physical methods.The stcreochcnrstry of iicxolic acid was mainly confirmed by X-ray single crystal diffraction method.     

Purification and Characterization of DNA Methylase From HL-60 Cells

A solid leukemia sarcoma has been successfully developed after subcutaneous inoculation of the cultured human promyelocytic leukemia cells (HL-60 cells) into unde mice. The solid leukemia sarcoma is a more plantiful source than the cultured cells for enzymatic study and its growing environment is closer to that of the human body than the cultured cells.We establish an efficient procedure of purifying HL-60 cells DNA methylase which includes: disruption of HL-60 cells by homogenization and sonication, removing the cell fragments and cellular particles by centrifuge and ultracentrifuge (105.000 g); removing endogenous DNA by streptomycin sulfate, salting out by (NH4)2SO4, ion exchange chromatography on DEAE-cellulose (DE-52), gel filtration over Sephadex G-100 column.The DNA methylase from HL-60 cells has been purified 204 fold by this procedure. The purified enzyme shows a single-band on PG-PAGE. A 479-kD molecular weight of this enzyme is measured by PG-PAGE. The enzyme properties of HL-60 DNA methylase     

SULFONATION OF A NEW POLYETHERETHERKETONE PREPARED FROM PHENOLPHTHALEIN

A novel polyetheretherketone (PEK-C) prepared from phenolphthalein has been synthesized. In order to improve some of its properties for application in high performance membrane, the PEK-C has been sulfonated with concentrated sulfuric acid. Degree of sulfonation can be regulated by controlling the temmperature and time of sulfonation. The characterization of the sulfonated PEK-C in sodium salt form has been made by IR, ~1H NMR and ~(13)C NMR etc. It is shown that the sulfonation appears to take place exclusively in the ortho position to phenolic ether of phenolphthalein unit. The result is in agreement with theoretical deduction. Some properties of the sulfonated PEK-C, such as solubility, transition temperature, thermal degradation and hydrophilicity have also been discussed.     

STUDIES ON RESPONSE CHARACTERISTICS OF DRUG ISE''''S (Ⅶ)——PERFORMANCE AND THEORETICAL TREATMENT OF MICROCELLS CONNECTED IN SERIES

A new type of MCCS (microcells connected in series) has been constructed and its performances investigated. It has been applied to the determination of streptomycin. The sensitivity and accuracy have been increased significantly. A theoretical model for the error of determination using the MCCS has been suggested and proved experimentally using the Monte Carlo method, and the error model proposed in Ref. [1] revised.     

Synthesis of N-Glycyl-2,3,4,6-tetra-O-benzyl-1,5-dideoxy-1,5- imino-D-glucitol

1-Deoxynojirimycin (1,5-dideoxy-1,5-imino-D-glucitol, DNJ) and its derivatives have been found to have a number of biological activities, such as anti-HIV, anticancer, anti-diabetic, etc.[1] N-Hydroxylethyldeoxynojirimycin (Miglitol)has been used as a drug for treating diabetic. N-Butyl-1-deoxynojirimycin (NB-DNJ) has show potent anti-HIV-1 and HIV-2 activity without cytotoxicity.[2] Recently, NB-DNJ has been approved for clinical trials as a potential therapy for some glycosphingolipid (GSL) lysosomal storage diseases, which belong to a group of severe and fatal human diseases[3]Therefore, it is very significant to study N-substituted compounds of DNJ.     

Synthesis and Expression of a Gene From Kringle-2 Domain of Tissue Plasminogen Activator in E. coli

The DNA fragment corresponding to the tissue plasminogen activator (tPA) sequence 174-262 (Kringle-2 domain) has been synthesized by using the solid phase phosphotriester method. The Kringle-2 domain of human tPA was expressed in Escherichia colt by secretion into the periplasmic space using the Lpp-Lac promoter and PIN-Ⅲ OmpA2 signal sequence. About two thirds of the expression product was secreted into the periplasmic space , and purified with ammonium sulfate fractionation, affinity chro-matography on Lysine-Sepharose, and FPLC-Mono Q exchange chromatography. The amino acid composition observed from the Kringle-2 purified from E. coli is identical with that expected for the 174-262 fragment of human tPA. Radio binding assay shows that the recombinant Kringle-2 domain possesses the activity of fibrin binding.