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Biomedical subjects

X Z Wu

Publications and source records attributed to X Z Wu.

At least 19 recordsLinked to original sources
PubMed2006

Sulfated oligosaccharides and tumor: promoter or inhibitor?

The topic about the role of sulfated oligosaccharides in carcinogenesis and progression of tumor remains controversial. The present review aims to evaluate the role of sulfated oligosaccharides in carcinogenesis and progression of tumor. The modification of sulfated oligosaccharides, especially chondroitin sulfate and heparan sulfate, is an important event in carcinogenesis and is correlated with the degree of differentiation. Enhance of chondroitin sulphate may promote carcinogenesis, while enhance of heparin sulphate may promote metastasis. Resistance of antiproliferation activity of sulfated oligosaccharides may contribute to the aberrant behavior of the cancer cell. Some researches supported that sulfated proteoglycan on the cell surface may enhance metastasis; while some soluble sulfated oligosaccharides could suppress metastasis. Thus, sulfated oligosaccharides play double roles, promoter or inhibitor, in carcinogenesis and tumor progression. Four topics about the correlation between sulfated oligosaccharides and carcinogensis and progression are very interesting and must be identified: whether the modified sulfated oligosaccharides have a different effect from the unmodified sulfated oligosaccharides; whether different sulfate oligosaccharides have the different action; whether the function of sulfated proteoglycan on the cell surface is different from that of soluble sulfated oligosaccharides; whether the function of sulfated oligosaccharides in primary tumor is different from that in metastasis tumor. Further data on the long-term safety of sulfate oligosaccharides for cancer patients are therefore required to allow overall risk-benefit assessments.

Carcinogens↗
PubMed2006

Cell-matrix talks: effects on differentiation of hepatocellular carcinoma.

Different event is a process that is dependent on stimulation of extracellular signals, signal transduction and gene express. Malignant transformation of hepatocytes may occur in cirrhosis, which is the result of extracellular matrix (ECM) remodeling. ECM could affect and maintain the differentiated phenotype of hepatocytes by regulating liver transcription factors. Moreover, ECM remodeling is correlated with dedifferentiation of hepatocellular carcinoma (HCC). Integrin-matrix adhesion system and E-cadherin/catenin adhesion complex mediate the cell-matrix interaction through focal adhesion kinase, extracellular-signal-regulated kinases and beta catenin/Wnt pathway. The different event of HCC compared with the reversion of abnormal cell-matrix interaction. New drugs that are power for regulating cell-matrix interaction may represent a novel therapeutic strategy for HCC.

Cadherins↗
PubMed2004

Surface and bulk interchange energy in binary mixtures of chain molecules.

The interchange (interaction) parameter, controlling the phase behaviour of a binary mixture, is determined for the bulk and the surface of binary mixtures of different types of chain molecules, using surface tensiometry and a mean-field theory. For all mixtures and concentrations studied an identical behaviour is observed at the surface, depending only on the square of the reduced chain length mismatch delta n/n, where delta n and dealta n are the difference in and average of the number of carbons of the two components.

Alcohols↗
PubMed2003

Surface freezing in binary mixtures of chain molecules. I. Alkane mixtures.

X-ray surface scattering and surface tension measurements are used to study surface freezing in molten mixtures of alkanes. These binary mixtures consist of protonated and deuterated alkanes, as well as of alkanes of different lengths. As for pure alkanes, a crystalline monolayer is formed at the surface a few degrees above the bulk freezing temperature. The structure of the monolayer has been determined on an angstrom scale. A simple theoretical approach is used to account for the thermodynamical observations at the surface and in the bulk. The model is based on a competition between entropic mixing and a repulsive interaction due to chain-length mismatch. The surface and bulk liquid phases are treated as ideal mixtures, while the solid phases are treated as regular mixtures. The theory is found to account well for all the mixtures studied, both hydrogenated-hydrogenated and hydrogenated-deuterated. The repulsive interaction and its dependence on the chain lengths of the components are determined from fits to the measured data.

Journal Article↗
PubMed2003

Antimicrobial susceptibility of Neisseria gonorrhoeae strains isolated in Guangzhou, China, 1996-2001.

OBJECTIVE: To investigate the in vitro antimicrobial susceptibility and resistant trends of Neisseria gonorrhoeae strains isolated in Guangzhou, from 1996 to 2001. METHODS: The agar dilution method was used to determine the minimum inhibitory concentrations (MICs) to four antimicrobials, penicillin G, ciprofloxacin, ceftriaxone, and spectinomycin. The resistance of all strains to four antibiotics was interpreted according to criteria used in the project of surveillance of gonococcal antibiotic susceptibility in the WHO Western Pacific Region. Penicillinase producing N gonorrhoeae (PPNG) was analysed by the paper acidometric method. RESULTS: 793 consecutive N gonorrhoeae isolates collected in Guangzhou were studied from 1996 to 2001. A total of 55 strains of PPNG were identified and the prevalence rapidly spread from 2% to 21.8%. Of the four antibiotics examined, ceftriaxone and spectinomycin appeared to be the most effective agents although two spectinomycin resistant strains were isolated in 1996. Their MIC(50), MIC(90), and geometric mean MIC (MICmean) were all between the sensitive ranges of the interpretative criteria and remained stable over the years. However, resistance increased continuously to penicillin G and dramatically to ciprofloxacin. In 1996-2001, MIC(50), MIC(90), and MICmean of penicillin G increased from 1 micro g/ml to 2 micro g/ml, 4 micro g/ml to 32 micro g/ml, and 0.68 micro g/ml to 2.35 micro g/ml, respectively; those of ciprofloxacin steeply increased from 0.12 micro g/ml to 4 micro g/ml, 2 micro g/ml to 32 micro g/ml, and 0.14 micro g/ml to 2.62 micro g/ml in 1996-9, respectively, and then declined slightly in 2000-1. The prevalence of resistant isolates spread from 57.2% to 81.8% for penicillin G and from 17.6% to 72.7% for ciprofloxacin over the 6 years. CONCLUSION: Resistance to penicillin and ciprofloxacin increased greatly during 1996-2001. Ceftriaxone and spectinomycin should be used as the first line agents in treating gonorrhoea. It is of great importance to continuously survey the susceptibilities of N gonorrhoeae to antibiotics in controlling the spread of gonococcal infections.

Anti-Bacterial Agents↗
PubMed2001

Dynamic realization of transport phenomenon in finite system.

Exploring the Fokker-Planck or Langevin type transport equation from the underlying dynamics, we study by exploiting the numerical simulations whether or not one may expect dissipative motions in a Hamilton system with finite degrees of freedom without introducing any statistical concept. It will be shown that the macro-level transport phenomenon in a finite system can be dynamically established from the underlying Hamilton system, and the nonlinear coupling between two subsystems is decisive for generating the transport phenomenon.

Journal Article↗
PubMed2001

Miniaturization of capillary isoelectric focusing.

Miniaturization of whole-column imaging capillary isoelectric focusing (CIEF) is discussed. A 1.2 cm capillary was used as a separation column for CIEF. The experimental results for the analysis of two pI markers and the protein myoglobin showed that good CIEF separation results could be obtained. Secondly, a light-emitting diode (LED) was used as the light source for the whole-column absorbance imaging detection. The focusing of both the pI markers and myoglobin were observed with the LED light source. The whole-column imaging CIEF instrument was simplified and miniaturized by the use of the LED. Further developments are also discussed.

Animals↗
PubMed2000

The effect of mutation at valine-45 on the stability and redox potentials of trypsin-cleaved cytochrome b5.

In an attempt to elucidate the determinants of redox potential and protein stability in cytochrome b5, three mutants at a highly conserved residue Val45, which is a member of heme hydrophobic pocket residues have been characterized. The V45Y mutant was designed to introduce a bulkier residue and a hydroxyl group to the heme pocket. The mutants V45H and V45E were constructed to test the effect of positive and negative charge on the stability and redox potential of proteins. The influence of these mutants on the protein stability towards thermal, urea, acid, ethanol and on the redox potential were studied. It is concluded that the decrease of hydrophobic free energy and the larger volume of the tyrosine make the phenylhydroxyl group of tyrosine still sitting inside the hydrophobic pocket, while the side chain of the mutant V45E and V45H shift away from the heme pocket. The redox potentials of mutants V45Y, V45H, V45E and wild-type of cytochrome b5 are -35 mV, 8 mV, -26 mV and -3 mV, respectively. The bigger change of the V45Y on redox potential is due to the close contact between the hydroxyl group and the heme, while the changes of the V45E and V45H result from the alteration of charge density and distribution around the heme. Different relative stability of these mutants towards heat have been observed with the order: WT > V45Y-V45H > V45E being both in the oxidized and reduced state. The relative stability induced by addition of urea decreases in the order: WT > V45Y > V45H > V45E. These results suggest that the difference in the hydrophobic free energy is a major factor contributing to the stability of the Val45 mutants. Also the loose of the helix III in the mutant V45E makes it more unstable. These results indicate that residue Val45 plays an important role in the stability and redox potential of the protein.

Acids↗
PubMed1998

Role of nitric oxide in vascular hyper-responsiveness to norepinephrine in hypertensive Dahl rats.

OBJECTIVE: To determine whether the abnormal vascular responses observed in salt-sensitive hypertension are caused by an impairment in vascular nitric oxide function. DESIGN: Isometric tension was measured in aortic rings isolated from Dahl salt-sensitive and salt-resistant rats fed a regular-salt (0.4% NaCl) or a high-salt (8% NaCl) diet, with and without inhibition of endogenous nitric oxide synthesis. METHODS AND RESULTS: Systolic arterial pressure, measured weekly by the tail-cuff method, increased markedly in DS rats with a high-salt diet but did not increase in the other groups. In aortic rings, norepinephrine evoked dose-dependent contractions which were significantly increased in rings from DS rats with a high-salt diet Pretreatment with Nomega-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, increased the norepinephrine-induced contraction in all groups and abolished differences in contractile responses between high-salt DS rats and the other groups. Acetylcholine induced endothelium-dependent relaxation, which was significantly depressed in high-salt DS rats. L-NAME attenuated the acetylcholine-induced relaxation in all groups and abolished the difference in relaxation response between high-salt DS rats and the other groups. Sodium nitroprusside-induced relaxation was significantly depressed in high-salt DS rats. CONCLUSIONS: Vascular hypercontractile responses to norepinephrine in DS hypertensive rats can, in part, be explained by an impairment in endothelial nitric oxide production.

Acetylcholine↗
PubMed1996

Separation and determination of some stereoisomers by capillary gel electrophoresis with cyclodextrin incorporated in polyacrylamide gel.

Capillary gel electrophoresis (CGE) was successfully applied to the separation of optically active isomers and position isomers by incorporating a suitable cyclodextrin chiral selector in polyacrylamide gel. A commercially available ss-cyclodextrin (ss-CD) was used for enantioselectivity towards o-, m- and p-nitrobenzoic acid, o-, m- and p-hydroxybenzoic acid, o-, m- and p-toluic acid and the optical isomers of dansyl-D,L-leucine and R,S-1,1'-binaphthyl-2,2-dihydrogenphosphate. Especially the effect of organic solvents, such as acetonitrile, methanol, dimethylsulphoxide and others were examined in detail. The resolution varied to some extent with the addition of the organic solvent to the polyacrylamide gel and the running buffer solution. The possible mechanism has also been discussed. In addition, quantitative aspects of the separation of stereoisomers using CGE have been studied, showing that both the resolution and accuracy of the determinations were affected by the ratio of the enantiomers.

Journal Article↗
PubMed1996

[Mechanism of injury of intestine, liver and lung in acute cholangitis of severe type model and the protective effect of huoxue qingjieling].

Lung capillary permeability was measured with 125I labelled bovine serum albumin, the progression of hepato-cellular injury was quantitatively assessed using atriphenyltetrazolium chloride assay, injury of small intestinal mucosa was determined by the changes of diamine oxidase (DAO) level, content of oxygen free radicals (OFR) was measured by electron spin resonance spectrometer and levels of phospholipase A2(PLA2) of intestine, hepatocellular viability were observed by bioassay methods respectively. The results showed that function of lung, liver and intestine was seriously injuried in ACST rats. These injuries demonstrated by increase of capillary permeability and decrease of hepatocellular viability as well as DAO in intestinal mucosa (P < 0.01) in comparing with control, while the levels of OFR and PLA2 in the above-mentioned 3 organs were elevated simultaneously (P < 0.01). As for the comparison of efficacy of different treatment, Huoxue Qingjieling was the best one, the bile duct decompression or ampicillin showed little benefit on injury protection even aggravated in some tissues, they displayed a close relationship with their influence on the OFR and PLA2. Besides, the levels of OFR or PLA2 in various tissues were different from each other, therefore, the serum levels of OFR or PLA2 can not reflect the real levels occurred in organ or tissue level.

Acute Disease↗
PubMed1995

Fluorescence imaging detection for capillary isoelectric focusing.

A simple laser-induced fluorescence (LIF) imaging detector and an ultrasensitive LIF imaging detector are described for capillary isoelectric focusing (CIEF). An argon ion laser beam of 496.5 nm is used as excitation source. In the simple LIF imaging detector, the excitation beam is directed into a capillary column by an optic fiber array. In the ultrasensitive LIF imaging detector, the laser beam is first expanded, then is focused into the 4.5 cm long capillary column by a cylindrical lens. Fluorescence emission is detected by a charge-coupled device (CCD) camera. The feasibility and performance of the LIF imaging detector system for CIEF are first verified with a naturally fluorescent protein, b-phycoerythrin. Then, the ultrasensitive LIF imaging system is used as a detector for CIEF of proteins labeled with fluorescein isothiocyanate (FITC). Three FITC-labeled proteins (i) alpha-D-galatosylated FITC-albumin, (ii) insulin-FITC, and (iii) casein-FITC, are used as model samples. Fluorescence images of the model samples are measured during the CIEF process. The focusing of the protein samples is complete in about 1.5 min. The ultrasensitive detector's detection limits for the FITC-labeled proteins are at the level of 10(-10) M, and the mass detection limits are about 4.5 x 10(-17) mole, even though only 10% of the fluorescence emission is collected. Therefore, the method is capable of separating and detecting 10(-11) M or amole (10(-18) mole) level protein samples with a band-pass filter more specific to the fluorescence light.(ABSTRACT TRUNCATED AT 250 WORDS)

Caseins↗
PubMed1994

Termination of early pregnancy by two regimens of mifepristone with misoprostol and mifepristone with PG05--a multicentre randomized clinical trial in China.

A multicentre randomized open clinical trial was conducted to compare the efficacy and side effects of two regimens of mifepristone with misoprostol, and mifepristone with PG05 for termination of early pregnancy (amenorrhoea < = 49 days). Six-hundred women in early pregnancy, who requested medical abortion were randomly allocated into 3 groups. In group 1 (n = 301), an initial dose of mifepristone 50 mg was given, followed by 25 mg every 12 hours up to a total dose of 150 mg mifepristone, plus a single oral dose of misoprostol 600 micrograms in the morning of the third day. In group 2 (n = 150), the same regimen of mifepristone was given, but dl-15-methyl PGF2 alpha (PG05) 1 mg vaginal suppository was inserted on the third day. In group 3 (n = 149), a single dose of mifepristone 200 mg was given and misoprostol 600 micrograms was used as in group 1. The complete abortion rate were 94.4%, 97.3%, and 94.6% for group 1, 2 and 3, respectively. 3.0, 2.0 and 2.7% of women had incomplete abortion, and 1.7, 0.7 and 2.0% of women in the 3 groups were treatment failures; in the remaining 1% in group 1 and 0.7% in group 3, treatment outcome could not be determined. There were no significant differences among the 3 groups. Lower abdominal pain was the main complaint which was reported by 82% of the subjects after PGs administration. The incidence of diarrhoea in PG05 group (38.7%) was significantly higher than that in the other two groups (21.6 and 20.1%) (P < 0.001), and so was vomiting. It was concluded that misoprostol, as an orally effective prostaglandin, in combination with mifepristone for induced abortion of early pregnancy was as effective as PG05 vaginal suppository. Besides, it has advantages of convenience of use, less side effects, easy storage and transfer, and low cost.

Abdominal Pain↗
PubMed1994

[Effects of dachengqi decoction on gut hormones and intestinal movement after cholecystectomy].

In order to elucidate the mechanism of postoperative intestinal dysfunction and the effects of Dachengqui Decoction (DCQD) on it, somatostatin (SS), gastrin (GAS), vasoactive intestinal polypeptide (VIP), substance P (SP), motilin (MOT) and atrial natriuretic peptide (ANP) were determined, frequency and spectrum of peristaltic sound were simultaneously analyzed in 31 subjects undergoing cholecystectomy, the value of pre-, post-operation and post-medication were compared. Plasma SS and MOT decreased postoperatively (P < 0.05), DCQD elevated SS and MOT to higher level than preoperation, VIP, SP increased for half fold (P < 0.05). Gurgling sound diminished after operation, whereas DCQD normalized it. Peak frequency (Fmax) of gurgling ranging from 234.4 to 468.2 Hz preoperatively, mean frequency (FA) was 341.8 +/- 30.9 Hz postoperatively. FA reduced to 322.3 +/- 79.4, DCQD elevated it to 374.2 +/- 57.1 Hz. The result suggested that intestinal motility was disturbed after cholecystectomy, bowel was in dystonic status, accompanying with decreased plasma MOT, DCQD promoted intestinal peristalsis and enhanced it's tonus. The influence of gut peptides might be one of the important pathway that DCQD works.

Adult↗
PubMed1994

[Long-term clinical observation on VCu200 intrauterine devices].

A comparative study was carried out in 350 women using VCu200 intrauterine devices (IUD) and 350 women using stainless steel ring (SSR) IUD for 5-18 years. The endometrial changes and shapes of IUD were studied. The results showed that the pregnancy rate was significantly lower in VCu200 group after 5 years of insertion. In spite of the oxidation, erosion or breakage of the copper wire, calcium deposit of even deformation of the IUD, they were not associated with an increased incidence of endometrial carcinoma and pelvic inflammatory disease. It is suggested that VCu200 IUD need not to be removed if the IUD keeps normal shape and the copper wire remains intact by X ray examination.

Endometrium↗
PubMed1994

[Effects of Tripterygiitotorum in the treatment of insulin dependent diabetes mellitus with islet transplantation].

UNLABELLED: The therapeutical efficacy of islet transplantation in treating insulin-dependent diabetes mellitus (IDDM) patients is marked for a short time and the long-term efficacy is unsatisfactory. So 30 IDDM patients given tripterygiitotorum (T II) were compared with 24 IDDM patients without using any immunosuppressive agents after islet transplantation. RESULTS: prior to transplantation both the numbers of T lymphocyte subpopulations such as CD2, CD4, CD8 and the concentrations of C-peptide in all IDDM patients were lowered; after transplantation the numbers of CD2, CD4 were significantly elevated (P < 0.01), the ratio of CD4/CD8 in control group was higher than that in TII group (P < 0.01), while the concentration of C-peptide were greatly increased (normal: 2.24 +/- 0.34; before transplantation: 0.21 +/- 0.01; 15 days after transplantation: 3.24 +/- 1.2 ng/ml). The peak value of C-peptide in TII group began decreasing half a year after transplantation and it gradually dropped to the baseline level. The dose of insulin all were significantly reduced, and 3 patients stopped altogether. Half a year after transplantation TII group remained stable for the requirement of insulin, whereas the control group gradually increased the dose of insulin. (1) Islet transplantation could adjust the immunological disorder in IDDM patients, increase the numbers of T lymphocyte subset such as CD2, CD4, CD8 while the chronic immuno-rejective response occurred. (2) T II inhibited both the numbers and function of T lymphocyte subpopulation and normalized the ratio of CD4/CD8. (3) TII prolonged the survival time of grafts in IDDM patients and suppressed immunological rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗