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Biomedical subjects

Z Wei

Publications and source records attributed to Z Wei.

At least 55 records · Page 3Linked to original sources
PubMed1999

[Statistical analysis of complications of the frontalis aponeurosis flap for correction of complete blepharoptosis].

OBJECTIVE: The cause of and prophylactic measures for the complications of the frontalis aponeurosis flap suspension for correction of blepharoptosis were investigated to improve the operative results. METHODS: Five hundred and thirteen patients who were found to have complications after frontalis aponeurosis flap suspension for blepharoptosis were studied by follow-up examinations. RESULTS: Fourteen kinds of postoperative complications were found and cured. CONCLUSION: Most of the postoperative complications following blepharoptosis correction can be prevented and well treated. The frontalis aponeurosis flap technique is reliable for correction of complete blepharoptosis.

Adolescent↗
PubMed1999

[Analysis of products of thymine irradiated by heavy ion beam with capillary gas chromatography].

In this study some chromatographic methods with capillary column, such as GC, GC-MS, GC-FTIR, were used to analyze the products of thymine irradiated by 18O8+ ion beam in N2O saturated aqueous solution. Because of the complexity and small amounts of the products after irradiation by heavy ion beams, it is very difficult to separate them, while with the methods of capillary gas chromatography this problem can be overcome. From the results of GC-MS analysis we can determine the molecular weight of the product, and from the results of GC-FTIR analysis we can get structure information of the product. By this way the products such as 5,6-dihydrothymine, 5-hydroxyl-5-methylhydantoin, 5-hydroxyl-6-hydrothymine, 5-hydro-6-hydroxylthymine, 5-hydroxymethyluracil, trans-thymine glycol, cis-thymine glycol and dimers were determined. Though these products are the same as those from thymine irradiated by gamma ray in N2O saturated aqueous solution, the mechanism of heavy ion beam interact ion with thymine aqueous solution is different from that of gamma ray. The main products from thymine irradiated by 18O8+ ion beam in N2O saturated aqueous solution are formed by hydroxyl additions between 5-6 band of thymine, while those by gamma ray are dimers of thymine.

Electrophoresis, Capillary↗
PubMed1999

[Analysis of the relationship between the facial skin temperature and blood flow].

The relationship between the blood flow of temperal or facial artery and facial skin temperature was studied in 30 patients with facial nerve paralysis. The facial skin temperature was recorded by infrared thermography, and the blood flow was measured by ultrasonic Doppler flowetry. The results showed, in the same facial region, the greater the volume of blood flow was, the higher the skin temperature stood. After acupuncture on the facial points, the facial blood flow increased and the facial skin temperature rose. The ratios between the increase in facial skin temperature and the in increase in blood flow were 0.9538-1.2835(degrees:ml/second) in four facial regions. These indicate the presence of certain quantitative relationship between the facial blood flow and the skin temperature.

Adult↗
PubMed1999

[Forecasting octane numbers of gasoline by NIR spectroscopy and the manufacture of octane number analyzer].

The predictive model of octane numbers, of gasoline was developed by using MLR and PLS method of chemometrics. It is applicable to forecast the MON, RON and PON of gasoline of catalytic cracking, catalytic reforming, alkylating as well as blended products. A near infrared optical multichannel analyzer (NIR-OMA) and a software package of octane number were developed. Combining both mentioned above a NIR-OM octane number analyzer was developed. With this NIR-OMONA one can obtain the MON, RON and PON (antiknock index) data in less than 1/2 minute with an accuracy of 0.6 ON unit and a precision of 0.1 ON unit by using 3-15 mL gasoline sample.

English Abstract↗
PubMed1998

Homology and functional similarity of an hrp-linked pathogenicity locus, dspEF, of Erwinia amylovora and the avirulence locus avrE of Pseudomonas syringae pathovar tomato.

The "disease-specific" (dsp) region next to the hrp gene cluster of Erwinia amylovora is required for pathogenicity but not for elicitation of the hypersensitive reaction. A 6.6-kb apparent operon, dspEF, was found responsible for this phenotype. The operon contains genes dspE and dspF and is positively regulated by hrpL. A BLAST search revealed similarity in the dspE gene to a partial sequence of the avrE locus of Pseudomonas syringae pathovar tomato. The entire avrE locus was sequenced. Homologs of dspE and dspF were found in juxtaposed operons and were designated avrE and avrF. Introduced on a plasmid, the dspEF locus rendered P. syringae pv. glycinea race 4 avirulent on soybean. An E. amylovora dspE mutant, however, elicited a hypersensitive reaction in soybean. The avrE locus in trans restored pathogenicity to dspE strains of E. amylovora, although restored strains were low in virulence. DspE and AvrE are large (198 kDa and 195 kDa) and hydrophilic. DspF and AvrF are small (16 kDa and 14 kDa) and acidic with predicted amphipathic alpha helices in their C termini; they resemble chaperones for virulence factors secreted by type III secretion systems of animal pathogens.

DNA Transposable Elements↗
PubMed1998

Fructus corni enhances endothelial cell antioxidant defenses.

1. The present study determined the effects of Fructus corni extract (FCE) on the levels of hydrogen peroxide (H2O2) and superoxide anion (O2-), on the glutathione (GSH) redox cycle and on the activities of antioxidant enzymes in bovine pulmonary artery endothelial cells (PAECs). 2. Confluent monolayers of PAECs were incubated with FCE, and oxidative stress was triggered by hypoxanthine and xanthine oxidase (to induce H2O2) or H2O2 (to induce O2-). 3. FCE exhibited a concentration-dependent suppression of H2O2 and O2-. 4. It modulated the GSH redox cycle by increasing the intracellular GSH content, the activities of GSH peroxidase and GSH disulfide reductase, and by decreasing the intracellular level of GSH disulfide. 5. It also increased the activities of superoxide dismutase and catalase. 6. These results demonstrate that FCE can promote a protective antioxidant defense state by affecting some important enzymatic and nonenzymatic oxidant-scavenging systems and may thus be useful for the prevention or treatment of disorders associated with oxidative damage.

Animals↗
PubMed1998

Stimulation as well as inhibition by antibiotics of the formation of GlcNAc-lipids of the dolichol pathway.

The antiobiotics, diumycin, amphomycin, bacitracin, and showdomycin have been shown previously to block the synthesis of GlcNAc-P-P-dolichol and GlcNAc-GlcNAc-P-P-dolichol. In view of inconsistencies in the literature concerning the sites of inhibition, we have reinvestigated the influence of these drugs on the formation of these early intermediates of the dolichol pathway. Unexpectedly, when the individual products of the reactions were examined, instead of inhibition, showdomycin and bacitracin were found to stimulate the formation of GlcNAc-P-P-dolichol, and diumycin stimulated at low concentrations. Three derivatives of showdomycin were examined with similar results, showing stimulations of GlcNAc-P-P-dolichol formation of up to two-fold over controls. Amphomycin specifically inhibited GlcNAc-P-P-dolichol formation, an effect that was reversed by a high concentration of dolichyl phosphate. In contrast, with the exception of amphomycin, each compound directly inhibited the formation of GlcNAc-GlcNAc-P-P-dolichol. Using chemically synthesized GlcNAc-P-P-dolichol as substrate, the kinetics of inhibition of GlcNAc-GlcNAc-P-P-dolichol formation by showdomycin, bacitracin and diumycin was examined. The apparent Ki values calculated from these studies indicated that showdomycin was the most active inhibitor. These findings provide a new understanding of the action of these compounds on the GlcNAc-transferases of the dolichol pathway.

Acetylglucosamine↗
PubMed1998

Fructus corni attenuates oxidative stress in macrophages and endothelial cells.

The antioxidant effect of a Chinese medicinal herb, Fructus corni extract (FCE), was investigated using models of oxidative stress in macrophages and vascular endothelial cells. Murine macrophages (J774) were incubated with FCE at 37 degrees C and 5% CO2 for 1 hr. Oxidative burst was triggered by zymosan and measured with a fluorescent probe. FCE exhibited a concentration- dependent suppression of oxidative burst. Confluent monolayers of bovine pulmonary artery endothelial cells (PAEC) were preincubated with FCE for 20 hrs, washed, and then exposed to an organic oxidant t-butyl hydroperoxide (tBHP) for 2 hrs. Cell viability was assessed by methylthiazol tetrazolium (MTT) assay, and cell injury by the release of intracellular lactate dehydrogenase (LDH). Lipid peroxidation products of PAEC were determined by measuring thiobarbituric acid-reactive substances (TBARS). Exposure of PAEC to tBHP resulted in decreased cell viability, increased LDH release, and elevated TBARS. Preincubation of PAEC with FCE significantly reversed these changes. Our results demonstrated that FCE can protect vascular endothelial cells from oxidant injury. The data thus suggest that Fructus corni may be useful for the prevention and/or treatment of disorders associated with oxidative damage.

Animals↗
PubMed1998

[Factors affecting the clinical pregnancy rate in an in vitro fertilization and embryo transfer program].

OBJECTIVE: To analyze the various factors in an in vitro fertilization and embryo transfer (IVF-ET) program which may affect the clinical pregnacy rate. METHODS: A retrospective study was done on 559 IVF-ET cycles from 1992-Nov. 1995. The indication for treatment was bilateral tubal blockage. The chi 2 analysis of single factor variants with SPSS-PC + V3.0 was used for statistics. RESULTS: The overall clinical pregnancy rate in 559 cycles was 21.6%. The cause of tubal blockage due to tuberculoses consisted of 28.4%, and 34.9% of secondary sterility had the history of artificial abortion. The changes of environment, the different causes of tubal blockage, the history of previous intrauterine pregnancy did not affect the clinical pregnancy rate. When the number of embryos transferred increased to 5, the clinical pregnancy rate was highest 32.5%. The cumulative embryo score or embryo quality was related significantly with clinical pregnancy rate. CONCLUSIONS: The number and quality of embryos transferred are important factors affecting the clinical pregnancy rate. However, measures to prevent high-order multiple pregnancy and studies on the survival potential of embryos besides their morphology should be emphasized.

Chorionic Gonadotropin↗
PubMed1998

[Analysis of X-ray images of giant-cell tumor of bone of rare locations].

OBJECTIVE: To analyse X-ray images of giant-cell tumor of rare locations. METHODS: To retrospectively review the X-ray films, CT scans and arteriograms of 48 cases of surgically and/or pathologically confirmed giant-cell tumor of bone of rare locations. RESULTS: Of the 48 cases, expansive cystic destructive changes of the bone with soap-bubble like appearence was found in 30 cases, osteolytic destruction in 10 cases, soft tissue mass outside of bone with sinking, flattening and local expanding of bone in 4 cases, invading into neighboring bone in 4 cases, hyperplasia and sclerosis of bone in 3 cases and staining of abnormal blood vessels and tumors in 3 cases. CONCLUSION: For the diagnosis of giant-cell tumor of bone of rare locations, X-ray plain film is of great value. CT is even better than plain film; arteriogram is helpful for diagnosis and treatment planning.

Adolescent↗
PubMed1998

[Effect of single alpha-particle on cells].

The mechanisms of biological effect of charged particles in space was studied through the inactivation effect of very low-density charged particles on very low-density cells at different impact parameters. A small type of microbeam facility with alpha-radioactive source and CN track detector were used. A diploid wild type Saccharomyces cerevisiae served as experimental eukaryotic cell. The correlation between cell inactivation and impact parameter of alpha-particles on cells was obtained through a CCD-camera system. The results showed that inactivation range of 1.13 MeV/u alpha-particles on cell-agarose mixture was about 5.5 micrometers, larger than the sum (about 3.l micrometers) of ion track-penumbra radius and yeast cell radius. The cell inactivation rate was 0.36-0.33. It suggests that multi-hit on a cell is necessary for killing it. However, in case of miss, the inactivation rate may not be zero at certain impact parameters.

Alpha Particles↗
PubMed1998

[Misdiagnosis of tired fracture of distal segment of femur].

OBJECTIVE: To improve the diagnosis of tired fracture of the distal segment of femur, and to avoid its misdiagnosis. METHOD: Misdiagnosis of 5 patients with tired fracture of distal segment of the femur was reviewed. RESULT: Five male patients, aged 18 to 23 years had the lesion for 3 to 6 weeks. They had long tough experience of sports. The lesion was considered at first as osteosarcoma by radiograph and biopsy. It was eventually diagnosed as tired fracture of distal segment of the femur. Symptoms were relieved or disappeared after proper treatment. Follow-up for 7 to 18 months showed good results. CONCLUSION: The key to avoid misdiagnosis and mistreatment of the fracture is to know its causes, morphological features of fracture healing, and correct pathologic diagnosis.

Adolescent↗
PubMed1998

[Study on the mitoxantrone carboxymethyl starch microspheres for hepatic artery chemoembolization].

In this paper, the technology for the preparation of plain carboxymethyl starch microsphere (CMS-MS) was optimized by the uniform design method with CMS-Na as carrier material and p-phthaloyl chloride as acrosslinker. The carboxymethyl starch microsphere loaded mitoxantrone (DHAQ-CMS-MS) was prepared by absorption method. Then, its morphology, size and size distribution, characteristics of drug loading, drug release in vitro, preparation for clinical application and its stability were studied. The pharmacokinetics of DHAQ-CMS-MS in rabbit was also studied. The results showed that the average diameter of the DHAQ-CMS-MS was 75.71 microns, drug loading was 13.21%, expansion ratio in water was 71.94%. The release of DHAQ in vitro from the microspheres was found to fit the model of single exponential function. The suspension prepared in this paper is not only convenient for clinical use, but also favorable for the improvement of the drug stability. The pharmacokinetic parameters obtained from the hepatic atery chemoembolization showed that the DHAQ-CMS-MS group, when compared with the solution group, exhibited a higher blood drug concentration in hepatic vein, its MRT was 1.96 times that of the solution group. As for the result of the peripheral vein, the MRT of the DHAQ-CMS-MS group was 1.95 times that of the solution group. This means that the drug when loaded in microsphere will be concentrated in its targeted site for a longer period, which is favorable for the treatment of hepatic cancer.

Animals↗
PubMed1998

[Determination of total Ca in the lung tissue of rats by FAAS].

Determination of total Ca in the Lung Tissue of Rats by FAAS was described, with a mixed microemulsion consisting of sodium dodecyl sulfate, N-dodecyl, N-dimethyl benzol ammonium bromide and nonyl phenol polyethyeneoxy ether. Comparing the result of the microemulsion FAAS with that of solution FAAS showed that the former was better than the latter in sensitivity, precision, selectivity and linearity of the calibration curve, with a detection limit of 1.92 microg x cm(-3), relative standard deviation of 1.92% (n = 10) and linear regressive coefficient of 0.9998 of the calibration curve over 0-20 microg x cm(-3) calcium. The method was applied to determine calcium amount in the lung tissue of rats, and the results were in accordance with those odtained by the conventional solution FAAS, in which a sample was reduced to ashes at a high temperature.

Analytic Sample Preparation Methods↗
PubMed1997

Multiple positive cis elements regulate the asymmetric expression of the SpHE gene along the sea urchin embryo animal-vegetal axis.

The mechanism that establishes the maternally determined animal-vegetal axis of sea urchin embryos is unknown. We have analyzed the cis-regulatory elements of the SpHE gene of Strongylocentrotus purpuratus, which is asymmetrically expressed along this axis, in an effort to identify components of maternal positional information. Previously, we defined a regulatory region that is sufficient to provide correct nonvegetal expression of a beta-galactosidase reporter gene (Wei, Z., Angerer, L. M., Gagnon, M. L., and Angerer, R. C., Dev. Biol. 171, 195-211, 1995). We have now analyzed this region intensively in order to determine if the spatial pattern is controlled by nonvegetal-positive activities or by vegetal-negative activities. The regulatory sequences, except the basal promoter, were mutated by either deletion or sequence replacement. None of these mutations resulted in ectopic beta-gal expression in vegetal cells, showing that no single negative cis element is responsible for the lack of vegetal SpHE transcription. Surprisingly, even short segments of the regulatory region containing only several identified cis elements also direct nonvegetal expression. Furthermore, the SpHE basal promoter functions effectively in vegetal cells in combination with cis-acting elements derived from the PMC-specific gene, SM50. We conclude that the spatial pattern of SpHE transcription is achieved by multiple positive activities concentrated in nonvegetal cells. The vegetal expression of SM50 also is regulated only by positive activities (Makabe, K. W., Kirchhamer, C. V., Britten, R. J., and Davidson, E. H., Development 121, 1957-1970, 1995). A chimeric promoter containing both SpHE and SM50 regulatory sequences is active ubiquitously, suggesting that these regulators are not reciprocally repressive. These observations suggest a model in which the SpHE and SM50 genes are activated by separate sets of positive maternal activities concentrated, respectively, in nonvegetal and vegetal domains of the early embryo.

Animals↗