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Biomedical subjects

Z X Li

Publications and source records attributed to Z X Li.

At least 19 recordsLinked to original sources
PubMed2005

Unusual micelle and surface adsorption behavior in mixtures of surfactants with an ethylene oxide-propylene oxide triblock copolymer.

Micellization and adsorption at the air-solution interface of binary mixtures of the triblock copolymer of ethylene oxide and propylene oxide, EO23PO52EO23 (EPE), and the surfactants sodium dodecyl sulfate (SDS), dodecyl trimethylammonium chloride (DTAC), and tetraethylene glycol monooctyl ether (C8EO4) have been studied by neutron reflectivity and surface tension. The synergistic attractive interaction between the polymer and the ionic surfactants has been analyzed in the framework of the pseudo phase approximation and gives rise to a stronger interaction for EPE/SDS than EPE/DTAC. In contrast, the interaction of the nonionic surfactant C8EO4 with the copolymer EPE shows an unexpected and rather different behavior, resulting in a strongly repulsive interaction, characterized by a positive interaction parameter. The neutron reflectivity measurements of the surface excess, where the predicted and measured surface excesses are directly compared, provide evidence that challenges the applicability of the pseudo phase approximation for describing the surface mixing behavior. Structural information on the mixed adsorbed layer provides evidence which in part explains the observed discrepancies between the measured surface excesses and the behavior predicted from the pseudo phase approximation. Furthermore the structural evidence can be use to rationalize the differences in behavior observed between the ionic and nonionic surfactants.

Journal Article↗
PubMed2001

[The design of axial pattern flap with color Doppler flow imaging technique].

OBJECTIVE: To study the effect of color doppler flow imaging(CDFI) technique in the design of axial pattern flap. METHODS: From April 1996 to June 1999, 10 patients with residual wound were adopted in this study. Among them, there were seven males and three females, the area of wounds ranged from 6 cm x 8 cm to 15 cm x 20 cm. Before operation, the axial pattern flaps were designed by traditional method, then CDFI technique with high frequency(5.0-7.5 MHz) was used for examining the major supply artery of the flap. At last, the modified flaps were transferred to cover the wounds. RESULTS: All the patients except one case completed the operation successfully. The cosmetic and function of the flaps were excellent. CONCLUSION: CDFI is a simple, direct and accurate method for detecting the supply artery of axial pattern flap. This technique should be popularized to avoid the blindness of flap design.

Adolescent↗
PubMed2001

Cladonia furcata polysaccharide induced apoptosis in human leukemia K562 cells.

AIM: To study whether Cladonia furcata polysaccharide (CFP-1) might induce apoptosis in human leukemia K562 cells. METHODS: Inhibition of proliferation was measured by MTT assay. Morphological assessment of apoptosis was performed with fluorescence microscope and electron microscope. DNA fragmentation was visualized by agarose gel electrophoresis. The amount of apoptosis cells was measured by flow cytometry. RESULTS: CFP-1 (50 - 800 mg/L) inhibited K562 cell proliferation in a concentration-dependent manner. After incubation of K562 cells with CFP-1 300 mg/L for 5 d, morphological changes of typical apoptosis were observed and agarose gel electrophoresis of DNA revealed "ladder" pattern. CONCLUSION: CFP-1 induced apoptosis in human leukemia K562 cells.

Antineoplastic Agents, Phytogenic↗
PubMed2001

[The development of the multifunctional cephalostat and its applications in anesthesia].

The multifunctional cephalostat is able to hold the patients' head better and firmly at prone position after tracheal intubation under general anesthesia According to the size of patients head, the anesthetist can properly adjust the distance of the malor holder and the distance between the superciliary ridge and the lower jaw, and fix the two tempora to prevent the head swaying. So this instrument greatly facilitates the anesthesia managements.

Anesthesia, General↗
PubMed2001

[Direct determination of selenium and bismuth in antimony and antimony compound by hydride generation-atomic fluorescence spectrometry].

The interference of Sb in determination of Se and Bi in antimony powder and antimony compound has been studied in different acidity, it is found that the interference of antimony has been reduced apparently in high acidity. Simultaneously, according to the difference of hydride generation reaction between Sb5+ and Sb3+, a sensitive and rapid method has been developed and used to determine Se and Bi in real samples. The recovery of the method is 95%-105% for practical samples. Detection limits are 0.00004 x 10(-2) (content) for Se and 0.0001 x 10(-2) mg.L-1 (content) for Bi respectively. The relative standard deviations of Se are 2.4% (content = 0.00169 x 10(-2) mg.L-1) and 5.4% (content = 0.00056 x 10(-2) mg.L-1). The relative standard deviations of Bi are 5.0% (content = 0.00024 x 10(-2) mg.L-1) and 1.3% (content = 0.00229 x 10(-2) mg.L-1). The method has been applied to determination of Se and Bi in practical samples with satisfactory results.

Antimony↗
PubMed2000

[Investigation on antibacterial activity of Forsythia suspense Vahl in vitro with Mueller-Hinton agar].

OBJECTIVE: To evaluate the antibacterial activity of Forsythia suspensa in vitro with different media. METHOD: MIC determination of Forsythia suspensa against Staphylococci was performed by the agar dilution method. RESULT: MIC90 of decoction of Forsythia suspensa against Staphylococcus epidermidis in M-H agar was 1:640, but in nutrient agar 1:40, the antibacterial activity with M-H agar being 16 fold higher than nutrient agar. CONCLUSION: The M-H agar should be recommended to replace nutrient agar as medium in the antibacterial experiment of Traditional Chinese medicine, and it is better to use multipoint inoculating device in the sensitivity test.

Agar↗
PubMed2000

[Observation on the persistence period and transmission of residual microfilaremia with medium and higher density].

OBJECTIVE: To explore the persistence period of medium and higher density of microfilaremia and its role in the transmission of filariasis in areas with filariasis basically eradicated. METHODS: The residual microfilaremia was followed up and the population were regularly examined by thick blood film assay. Culex quinquefaciatus were dissected to determine the natural infection rate and density of filarial larvae. The filarial antibody levels were detected by using IFAT. RESULTS: Two cases with medium and higher density of microfilaremia were found to be microfilaremia positive for twelve years. The natural infection rate and density of filarial larvae in Culex quinquefasciatus dropped down year by year, one case of new microfilaremia was found in the sixteenth year. CONCLUSION: The persistence period of residual medium and higher density of microfilaremia lasted for more than twelve years. The individual residual medium and higher density of microfilaremia cases still possess the potential for transmission of filariasis.

Animals↗
PubMed2000

[Studies on the recurrent attacks of acute adenolymphangitis due to Malayan filariasis].

OBJECTIVE: To explore the role of filarial and bacterial infections in the recurrent attacks of acute adenolymphangitis due to malayan fialriasis. METHODS: 1. To observe the seasonal fluctuation of acute attacks by performing monthly follow-up on patients with history of acute attacks in recent years. 2. To study the relationship between bacterial infection and filarial adenolymphangitis by performing bacteria culture and anti-streptolysin O test. 3. To investigate the variation of acute attacks by controlling filariasis transmission or by treating patients with a history of recurrent acute attacks. RESULTS: 1. The peak of acute attacks in patients coincided with the peak of vector transmission season. 2. Of the 97 cases examined by bacteria culture, 90 cases were negative; of the 255 cases examined by anti-streptolysin O test, the titres in 94.1% (143/152) of the cases with first attack and simple adenolymphangitis were within normal limits, however, the titres in 27.2% (28/103) of the cases complicated with elephantiasis were increased. 3. The acute attack rate of adenolymphangitis per year reduced significantly in cases with first attack and simple adenolymphangitis after effective control of filariasis transmission. 4. There was no evidence of the reduction of acute attacks by treating patients with DEC alone. CONCLUSION: In malayan filariasis endemic areas, the main causes of recurrent attacks of acute adenolymphangitis might be the repeated filarial infections due to the persistence of filariasis transmission.

Acute Disease↗
PubMed1998

Cholesterol efflux effect of high density lipoprotein is impaired by whole cigarette smoke extracts through lipid peroxidation.

It has been reported that high density lipoprotein (HDL) plays an anti-atherogenic role by stimulating cholesterol efflux from the foam cells in the atheromatous lesion. In this study, we prepared a novel modified form of HDL (CS-HDL) by incubating HDL with whole cigarette smoke (CS) extracts containing both particulate matter and gas-phase smoke, and examined its effect on cholesterol efflux. CS-HDL showed a marked increase of conjugated dienes and denaturation of apoA-I, a major protein component of HDL. The cholesterol efflux effect of CS-HDL was remarkably reduced to the same level as that of oxidatively modified HDL induced by copper ion (Ox-HDL). Addition of 20 microg/ml superoxide dismutase (SOD) during the CS-modification of HDL caused retrieval of cholesterol efflux activity by 53% and a remarkable decrease in the conjugated dienes level. SOD, however, had no ameliorative effect on apoA-I denaturation. When HDL was incubated only with gas-phase smoke (gasCS-HDL), neither increase of conjugated dienes nor impairment of the cholesterol efflux effect was observed, whereas apoA-I was denaturated to the same extent as seen in CS-HDL. These results indicate that whole CS-extracts, but not gas-phase smoke, reduces cholesterol efflux effect of HDL and that lipid peroxidation associated with superoxide anion is involved in this functional impairment.

Animals↗
PubMed1997

PCR-based genotyping of MNSs blood group: subtyping of M allele to MG and MT.

PCR-based genotyping of MNSs blood group system was investigated in combination with restriction fragment length polymorphism (RFLP), single-stand conformation polymorphism (SSCP) and allele-specific PCR amplification (ASPA) techniques. M and N alleles are based on three nucleotide substitutions in exon 2 and one base change (G or T) in an intron of glycophorin A locus. The latter single base change was also found among M alleles analyzed in this study, so that M allele appeared to be subdivided into MG and MT. All three alleles, MG, MT and N were identified clearly by RFLP or SSCP analysis following a single amplification. S and s alleles are based on one nucleotide substitution in exon 3 of glycophorin B gene. Genotyping of Ss blood group system was also explored by PCR-SSCP or ASPA analysis, and problems in the methods were discussed.

Alleles↗
PubMed1997

[Studies on isolation, purification and structure of polysaccharide RHG from Hedysarum polybotrys Hand.-Mazz].

A water-soluble polysaccharide, RHG, was isolated from the roots of Hedysarum polybotrys Hand.-Mazz. It was shown to be homogeneous by electrophoresis and gel filtration. Its average molecular weight was estimated to be 1.4 x 10(4). Methylation analysis, periodate oxidation, Smith degradation, IR, NMR and KI-I2 reaction showed that RHG is a (1-4) linked alpha-D-glucan to which the glucosyl side chains are attached at O-6 of the glucosyl residues of the main chain.

Drugs, Chinese Herbal↗
PubMed1996

Nested deletions from a fixed site as an aid to nucleotide sequencing: an in vitro system using Tn3 transposase.

We have previously constructed a cloning/sequencing vector, with an in vivo system capable of creating nested deletions from the end of transposon Tn3, which is useful for sequencing large DNAs. Here we report an in vitro system which uses an ammonium sulfate fraction of extract from E. coli cells harboring a Tn3 transposase overproducer plasmid to generate nested deletions. A key feature of the procedure is exhaustive digestion of the reaction products with a restriction enzyme that cleaves only between the Tn3 "right" terminus and the cloned fragment. This step reduces the noise level due to mechanisms other than deletions from the Tn3 terminus, and facilitates detection and isolation of the desired deletion products. This system enables us to save at least 2 days' time when obtaining the necessary deletions compared with the in vivo system.

Bacteriophage lambda↗
PubMed1996

Small balloon catheters in the induction of labour in mid-trimester pregnancy.

Labour induced in 46 women with a small balloon catheter was compared to 46 women induced with 'normal balloon' (Robinson's catheter with two condoms) and matched for age, parity, gestational age, marital status and ethnic origin with the aim of identifying a preferred induction method for middle trimester pregnancy. The retrospective study showed no differences in the duration of delivery, Pitocin, mode delivery, complications and effective rate. 'Small balloon' is simpler than 'normal balloon' and is a safe, reliable induction of labour method for mid-trimester pregnancy.

Abortion, Therapeutic↗
PubMed1996

[Effects of aspirin and nifedipine alone or in combination on hemodynamics in anesthetized dogs].

AIM: To study the effects of the combination of aspirin (Asp) and nifedipine (Nif) on hemodynamics in 8 anesthetized dogs. METHODS: Tension time index (TTI), left ventricular work index (LVWI), mean arterial pressure (MAP), and total peripheral vascular resistance (TPVR), femoral artery blood flow (FBF), ventricular systolic pressure (LVSP), maximum of its first derivative (dp/dt(max)), left ventricular end diastolic pressure (LVEDP) and heart rate (HR) were recorded on polygraph and electromagnetic flowmeter. RESULTS: Asp 5, 10 mg.kg-1, i.v. exerted a significant effect on the hemodynamic indices, wheras Nif 15 micrograms.kg-1, i.v. decreased TTI, LVWI, MAP, and TRVR, increased FBF distinctively, and slightly affected LVSP, dp/dt(max), LVEDP, and HR. The effects of Asp in combination with Nif on hemodynamics were similar to those of Nif alone. CONCLUSION: The improvement of cardiovascular function caused by Nif was not affected by the presence of Asp.

Animals↗