Search PubMed⌕ Search

Biomedical subjects

S Zhang

Publications and source records attributed to S Zhang.

At least 721 records · Page 40Linked to original sources
PubMed1998

[A study of cytokines in pathogenesis of thyroid-related immune orbitopathy].

OBJECTIVE: To explore the pathogenesis of thyroid-related immune orbitopathy (TRIO). METHODS: Human orbital fibroblasts were cultured in vitro and immunohistochemical techniques were used to study cytokines that induce effect on HLA-II antigen expression of orbital fibroblasts. RESULTS: It is shown that interferon-gamma (IFN-gamma), interleukin-1 (IL-1) and tumor necrosis factor (TNF) could induce the expression of orbital fibroblast HLA-II antigens. The induced effect of IFN-gamma is of good linear correlations with time and concentration. CONCLUSION: HLA-II antigen expression can be induced by IFN-gamma, IL-1 and TNF. In the course of immune reaction and pathogenesis of TRIO, cytokines play important roles.

Cytokines↗
PubMed1998

[Determination of diterpenoic acid, triterpenoids and tritersaponins in Aralia by RP-HPLC].

In this paper, an accurate RP-HPLC method for the determination of oleanolic acid 28-O-beta-D-glucopyranoside (I), oleanolic acid 3-O-alpha-L-arabinopyranoside (II), 3 beta-hydroxy-oleana-11, 13(18)-dien-28-oic acid (III), (ent)-pimara-8(14), 15-dien-19-oic acid (IV), oleanolic acid (V) and 3-ox-oleana-12-en-28-oic acid (VI) in 11 species of Aralia Linn. was described. The analytical column used was Supelco SIL-LC-18. The mobile phase was MeOH-1%HOAc-THF (500:110:1, pH 3.4). The flow rate was 1.2 ml.min-1. The detection wavelength was 205 nm. The linear ranges of I-VI were 0.135-2.160, 0.163-2.610, 0.123-1.962, 0.068-1.080, 0.135-2.160 and 0.248-2.646 micrograms, respectively. The recoveries of I-VI were from 86.88% to 93.31%. Detailed comparison of the diterpenoic acid, triterpenoids and tritersaponins for the group of herbal with those of woody the content of diterpenoic acid in herbal is higher than that of in woody. It showed that the diterponic acid is the specific constituent in the group of herbal, which is the difference to woody. This conclusion provides the evidence of the chemical classification for dividing the groups of herbal and woody into two distinct subgenus.

Aralia↗
PubMed1998

[Synthesis and antiulcer activity of 3,4-dihydro-hainanensine analogs].

In order to search for new compounds with new mode of action, high antiulcer activity and lower toxicity, 26(13 pairs of diastereoisomer A and B) 3,4-dihydro-hananensine analogs were synthesized. All compounds were tested in M1 receptor combined assay and gastric ulcer induced by cold-immersion stress in rats. Most compounds showed antiulcer activity, among them IX3A, IX7A, IX8A, IX12A, IX12B and IX13A exhibited more potent antiulcer activity than the control compound cimetidine. Meanwhile, the relationship between their structures and activity was discussed.

Animals↗
PubMed1998

[Solid-phase extraction coupled with high-field proton nuclear magnetic resonance spectroscopy: application to the analysis of brodimoprim metabolites in rat urine].

The use of coupled solid-phase extraction and high-field proton nuclear magnetic resonance spectroscopy (SPE-1HNMR) for the detection and identification of the urinary metabolites of brodimoprim is described. Urine was obtained from Wistar rats following a dose of 200 mg.kg-1 of brodimoprim. Analysis was performed on partially purified extracts obtained by solid-phase extraction onto C-18 bonded silica gel. As each spectrum was often given by a mixture of more than two kinds of metabolites, stepwise identification of the individual metabolites was achieved by sorting out signal sets having invariant proportionality. Five kinds of metabolites of the drug were found by the analysis.

Animals↗
PubMed1998

[X-ray diffraction Fourier Pattern Analysis of the Chinese materia medica "shannai" (Kaempferia Galanga L.)].

Every Chinese materia medica consists of dozens of ingredients. It is a multiingredient system. X-ray diffraction provides a way to determine Chinese materia medica in diffraction space which can reflect the general structural characteristics of Chinese materia medica and quantitative changes of partial ingredients. Considering the influence of varieties, growing places, growing periods, collecting seasons and other phenological factors, we selected 6 samples of Kaempferia galanga L. and Kaempferia marginata Carey, collected in different seasons from different growing places for X-ray diffraction Fourier Pattern Analysis. We have obtained characteristic peaks and diffraction fuzzy figures for distinguishing purposes. The result shows that X-ray diffraction Fourier Pattern Analysis can be used for distinguishing Chinese materia medica with similar shape and properties, similar tissue texture or similar chemical composition.

Drug Contamination↗
PubMed1998

[Synthesis of 1,4-dihydropyridines with blood pressure and blood-fat lowering effects].

To develop new drugs with the effects of lowering blood-fat and blood pressure, compounds 1-7 and 10 were synthesized by the reactions of 2-methyl-2-[4-(4-chlorobenzoyl)phenoxy]propionyl chloride with a hydroxyl group in 1,4-dihydropyridines. Compounds 8 and 9 were obtained by the reactions of 2-methyl-2-[4-(4-chlorobenzoyl)phenoxy]propionyl chloride with salicylic aldehyde first, and then with beta-aminocrotonates. All 1-10 are new compounds, and their structures were elucidated by means of 1HNMR and MS. The effects of compounds 1-10 on lowering cholesterol, triglyceride and blood pressure were investigated, and some of which were found to have the effects of lowering triglyceride and blood pressure.

Animals↗
PubMed1998

Immunoscreening of Schistosoma japonicum egg cDNA library.

AIM: To screen and identify genes encoding vaccine candidates and molecules with diagnostic potential from S. japonicum (S. j) egg cDNA library. METHODS: S. j egg cDNA library was screened by sera from SEA-immunized rabbits. Positive clones were identified after three rounds of screening and were excised automatically in vivo with helper phage. Products of PCR were used to detect insert sizes by agarose gel electrophoresis. DNA samples were obtained by purification using mini-prep kit. Automatic sequencing was carried out and the sequence data were analysed using GCG software. RESULTS: Twelve clones were identified as positive and the inserts were around 1.2 kb in size. Compared with DNA sequences in GenBank, eight clones were homologous to a 70 kDa S. j heatshock protein(S. j HsP70). C18 exhibited 97.8% homology with S. j23. C22 and C23 shared 82.4% and 89.5% homology with S. j calreticulin, respectively. C12 was homologous to S. mansoni(S. m.) immunophilin. CONCLUSION: This paper first reported the results of immunoscreening S. j egg cDNA library by anti-SEA sera. Twelve positive clones were found to be related to protective immunity and/or immunodiagnosis of schistosomiasis.

Animals↗
PubMed1998

[Establishment of a method for detecting anti-HCV IgM using recombinated structural region antigens].

Presence of IgM antibody to viral structural protein can be taken as the marker of its replication, so the detection method for anti-HCV IgM was established using as HCV recombinated structural region antigens, including C, E1, E2, as the coated antigen and rabbit anti-human gamma chain sera for neutralization and sheep anti-rabbit IgG coated for the sorbence of the complex of RAH-gamma with human IgG. 76 serum specimens of the hepatitis C patients were detected by indirect ELISA for anti-HCV IgM and by RT-PCR for RNA. The results suggested that IgM antibodies to C, E1, E2 were closely related with RNA (P < 0.005). The components of the IgM antibody, too were identified by indirect ELISA with recombined antigens coated respectively. When whole-fragment C or C + E2 were used as the coated antigens, anti-HCV IgM in 96.6% or 100% of serum specimens can be respectively detected. Using recombined structural region antigens, detection of anti-HCV IgM by ELISA was high sensitivity and specificity.

Antibodies, Viral↗
PubMed1998

[A micro transducer for dynamic multi-location pH monitoring in upper digestive tract].

A new transducer catheter used for dynamic multi-location pH monitoring in upper digestive tract has been developed. On the catheter several antimony electrodes and an Ag-Agcl electrode are integreted. An animal experiment compared the results of gastric aspiration and dynamic recording and demonstrated the reliability of this transducer. Clinical application has shown that this technology contributes greatly to the research on digestive physiology and to the diagnosis of functional diseases such as non-cardiac chest pain.

Animals↗
PubMed1998

[Purification and characterization of cyclomaltodextrin glucanotransferase from alkaliphilic bacteria].

A cyclomaltodextrin glucanotransferase from alkaliphilic bacteria was purified to PAGE homogenous by ammonium sulfate precipitation and DEAE-cellulose DE-52 chromatography with 11.5 fold purification and 5.7% recovery. Mr estimated with concentration gradient PAGE was 151,000. The optimum conditions for activity were pH 7.0, temperature 60 degrees C, stable in the range 6.0-9.0 and below 50 degrees C. The enzyme activity was activated by salicin and maltitol, slightly inhibited by Sn2+, Mn2+, inositol and pullulan, strongly inhibited by Ag+, Cu2+, Al3+, Fe2+, Pb2+, Hg2+ and Zn2+. The maximum absorption was at 270 nm in ultraviolet spectrum, the maximum emission wavelenghth in the excitation spectrum was 283 nm, the maximum emission spectrum determined at 283 nm was 335 nm. The effects of some protein modification reagents on the CGTase activity have been studied. Histidine and tryptophan residues may be essential for activity, carboxyl groups might have some effects on the activity.

Bacteria↗
PubMed1998

[Studies on the selection of strains producing colominic acid and culture conditions].

One strain E. coli C-8, the highest yield of colominic acid, was selected from 40 E. coli strains in the medium in which glucose and ammonium sulfate were the only carbon and nitrogen resources. An optimum medium for the growth and colominic acid production of E. coli C-8 was studied. The optimum carbon resources for colominic acid production was sorbitol selected from 16 kinds of carbons, and its optimum concentration was 2.5%. The optimum inorganic and organic nitrogen resources for colominic acid production were ammonium sulfate (0.5%) and tryptone (1.5%), respectively. The optimum concentration of K2 HPO4 was 90 mmol/L. The optimum culture temperature was 37 degrees C, but no colominic acid was produced below 20 degrees C. The optimum pH range was 7.5-8.2. The strain growth in the optimum medium kept logarithmic phase in 40 h (maxim A = 22). The colominic acid secreted into medium was much lower before 20 h, but high biosynthetic rate of colominic acid was detected after 40 h, the colominic acid reached the highest level (1,200 micrograms/ml) at 65 h.

Culture Media↗
PubMed1998

[Studies on the oxidation reaction of octanol-2 with nitric acid by infrared spectroscopy].

In this paper, the reaction process of oxidation of octanol-2 with nitric acid has been studied by IR spectroscopy. It is found that the main components of non-sapoifiable matter are different in different oxidation degrees. The relation between oxidation products and the amount of nitric acid are investigated,the reaction mechanism has also been studied. Experimental results show that the oxidation process of octanol-2 is as follows: first, octanol-2 is oxidated to octanone-2, or to nitrate, nitrite and nitrile copmpounds, then these compounds are reoxidated to caproic acid in the meantime some by-products, such as valeric, enanthic acids are also found in oxidated products.

English Abstract↗
PubMed1998

[FTIR microscope study on the change of membrane protein and lipids of erythrocyte damaged by free radicals].

The FTIR Microscope and Computer Aided Analysis were used to study not only the change of secondary structure of erythrocyte membrane protein attacked by the free radicals, but also the effect of oxygen centered free radicals on the membrane lipids in this paper. The results indicate that the content of alpha-helix in the secondary structure of protein clearly changed because of the attack of the free radicals. Damaged by free radicals in 30 minutes, the protein structure could not be restored after 3 hours. The number of the P=O (vp=0), C=O and C=C in the lipids of the membrane was changed. These changes were caused by the peroxidation of the oxygen centered free radicals.

Adult↗
PubMed1998

[Simultaneous determination of germanium and molybdenum in mixtures by complexation with 5'-nitrosalicyfluorone and dual-wavelength standard addition spectrophotometry].

In the presence of hexadecyltrimethylammonium bromide and in a medium of 0.3-0.9mol/L sulfuric acid, germanium (IV) and molybdenum (VI) react with 2,6,7-trihydroxy-9 (2'-hydroxy-5'-nitro) phenylfluorone-3, i.e., 5'-nitrosalicyfluorone, to develop red complexes, respectively. The spectra of the two complexes overlap seriously each other, and the additivity of their absorbances is good in the wavelength range of 490-548nm. So a new method for simultaneous spectrophotometric determination of germanium and molybdenum by dual-wavelegth standard addition method has been investigated in detail. The analytical results of five standard mixtures are more accuracy than those obtained by isobestic-point dual-wavelength method. The method has been applied to the analysis of traditional chinese medicine and mineral water with satisfactory results.

Drugs, Chinese Herbal↗
PubMed1998

[Study of determination method for trace cobalt in serum of cancer patients].

A method for the determination of micro amount of Co in serum of cancer patients by GFAAS has been established. The effect of protein in serum was eliminated by adding (1+1) HNO3. The blood serum was determined directly by adding Triton X-100 and NH4VO3 as matrix modifier. The method is handy and fast. The rate of recovery is 97.60-102.21% with RSD < 7.21.

Blood Chemical Analysis↗