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Biomedical subjects

Z Yu

Publications and source records attributed to Z Yu.

At least 289 records · Page 16Linked to original sources
PubMed1996

[Therapeutic effect of trace element on ulcerative colitis experimental study].

OBJECTIVE: To produce a chronic UC model in rats, and study the therapeutic effects of trace elements on this UC model as well as the in possible mechanisms. METHODS: Male Wistar rats (100-150 g) were given drinking water containing 1.5% dextran sulfate sodium (DSS) to induced UC. Rats developed UC were divided into 4 groups randomly, selenium group (Se group, Natural Selenium Liquid 6 ml.d-1, containing selenium 60 micrograms); zinc plus selenium group (ZS group, every rat was given zinc sulfate 180 mg.kg-1.d-1 and selenium 60 micrograms.d-1), while dexamethasone (7 mg.kg-1.d-1) was used as positive control and 0.9% NS as placebo control. All rats received enema twice a day for 15 days. Endoscopic and histologic scoring were carried out for assessment of the therapeutic effect of trace elements. Mucosal SOD activity, MDA content, zinc and selenium content and peripheral blood NK activity were assessed. RESULTS: The efficacy of ZS group was better than that of placebo control (P < 0.01), and there was no difference between ZS group and positive control (P > 0.05). An increased SOD activity and decreased MDA content were found after the combined administration of zinc and selenium. Zinc and selenium concentration of colonial mucosal were increased significantly, so did the NK activity of peripheral blood. CONCLUSION: The combined therapy of zinc and selenium is effective for UC treatment, of which the possible mechanism may be involved, A) concentrating in local mucus; B) acting as scavengers of oxygen-free radicals, protecting cell membrane from peroxidation; C) improving the function of immunosurveillance system.

Animals↗
PubMed1996

[Detection of micrometastases in axillary lymph nodes of node-negative breast cancer patients and its clinical significance].

Monoclonal antibodies against cytokeratin (AE1/AE3) were applied as a prob, using APAAP immunohistochemistry technique to detect 635 lymph nodes from 45 breast cancer patients with negative lymph nodes. Micrometastases were identified in 14 lymph nodes of 9 cases (20%). A significant difference was found between cytokeratin staining positive group and cytokeratin staining negative group in disease-free and over-all Kaplan-Meier survival curves. The detection of micrometastases had more clinical value for T1 and T2 patients. One of 2 T1 cytokeratin positive cases relapsed while only 1 of 19 T1 negative cases relapsed within 5 years, three of 5 T2 cytokeratin positive cases relapsed while 1 of 17 negative cases did. The presence of micrometastases had the same value in predicting local recurrence and distant metastases.

Adenocarcinoma↗
PubMed1996

[The influence on radioulnar joints after single-bone fracture of the forearm in children].

For the sake of researching overgrowth after single-bone fracture of the forearm in children, 179 patients were reviewed, the range of follow-up was 5-8 years, mean 7.5 yrs. (Not including Montaggia's, Galeazzi fracture's and physeal injuries). Bilateral comparative X-ray assessments were as follows: length of ulna and radius, radioulnar angle, ulnar deviation angle and anteversion angle of the radius, radial capitular line, position of the humeral head, and the movement of wrist and elbow joint. Overgrowth of the fractured bones existed only in 4 patients' by the length of 2-4 mm. Movements of wrist and elbow joints were normal. As the forearm is a double-bone balanced extremity, the injury is not very severe after single-bone fracture and overgrowth is usually hard to be observed.

Adolescent↗
PubMed1996

[Protective effects of beta-carotene liposome against rat neutrophile membrane damage caused by intra- or extra-cellular reactive oxygen species].

In this experiment the protective effects of beta-carotene (beta-C) liposome against rat neutrophile membrane damage caused by extracellular or intracellular reactive oxygen were species (ROS) investigated by means of fluorescence labels 1, 6-diphenyl-1,3,5 hexatriane (DPH) and N-(3-pyrene) maleimide (N-(3p)M). The extracellular ROS include the singlet oxygen (1O2) generated by photoreaction of sensitizer rosebengal and the superoxide anion (O2-.) produced by xanthine/xanthine oxidase reactive system. The intracellular ROS was sensitizer rosebengal and superoxide anion (O2-.) produced by xanthine/xanthine oxidase reactive system while the intracellular oxygen was generated by stimulating neutrophile respiratory burst with opsonized zymosan. No change in the peak or shape of fluorescent excitation and emission spectra was found for either of the two labels. The results of fluorescent polarization value in the membrane showed that beta-C liposome could significantly inhibit the damage of rat neutrophile membrane protein reacted either by intracellular generated reactive oxygen species or by extracellular generated O2-. or 1O2. It could also inhibit the injury of the rat neutrophile membrane lipid reacted by extracellular reactive oxygen species. However, the protective effects of beta-C liposome against membrane lipid damage reacted by intracellular reactive oxygen species by at the same concentration as those on membrane protein were not significant, which could be partly explained by relatively higher damage level of rat neutrophile membrane lipid domain reacted by intracellular reactive oxygen species than that of the membrane protein domain.

Animals↗
PubMed1996

[Conservative treatment for early breast cancer].

68 Cases of early breast cancer were divided into local resection group (33 cases) and local resection plus axillary dissection group (35 cases). The 3-, 5- and 10-year survival rate of the two groups were 97.0%, 78.8%, 72.7% and 94.3%, 80.0%, 77.1% respectively; The metastasis rate of the two groups were 6.1%, 12.1%, 3.0% and 8.6%, 17.1%, 8.6% respectively; and the local recurrence rate of the two groups were 6.1%, 6.1%, 3.0%, and 5.7%, 5.7%, 2.9% respectively ( P > 0.05). The cosmetic satisfaction rate of the two groups were 60.6% and 65.7% respectively ( P > 0.05). Factors relating to cosmetic results were type of breast, operative incision, age and postoperative radiotherapy. Conservative operation for early breast cancer was safe, provided incision margin was 2 cm approximately 3 cm. In all patients mammplasty was performed after tumor resection, and contralateral breast were treated by mammominification when it was necessary.

Adenocarcinoma↗
PubMed1996

[Characterization of insecticidal crystal proteins of Bacillus thuringiensis subsp. chinensis CT-43].

Bacillus thuringiensis subsp. chinensis CT-43, no flagellum, produces various shaped parasporal crystals, which consist of 140000, 130000, and 65000 proteins. Based on two kinds of mutant, 140000 and 130000 crystal protein individually forms bipyramidal crystal and the 65000 protein forms cubidal crystal, and that the 140000 and 130000 protein is activated by trypsin into 55000 and 66000 proteins and 60000 protein, respectively. Bioassay were conducted to 3rd instar Plutella xylostella larvae with crystals, soluble crystal proteins, and activated crystal proteins, respectively, and it indicated that high toxic mutants can be obtained by curing low toxic crystal genes, and that the toxicity of crystals can be improved 16.3 to 58.4 times after solubilization.

Animals↗
PubMed1996

Effects of m-nisoldipine on aortic calcium accumulation in rats with vascular calcium overload.

AIM: To study the effects of a novel calcium channel blocker, m-nisoldipine, on vascular calcium overload (VCO) at both tissue and cellular levels. METHODS: VCO was induced in Wistar rats by treatment with colecalciferol (Col, 400,000 IU.kg-1, p.o.) and an aqueous mixture of ethanol and polyethyleneglycol-400 for 3 d. The tissue and subcellular calcium contents of aorta were determined by atomic absorption spectrometer and electron probe microanalysis, respectively. RESULTS: Chronic treatment with m-nisoldipine (m-Nis, 1-15 mg.kg-1, p.o., bid) only had mild inhibition on the elevation of total calcium in aorta, and the dose-response relationship of m-Nis displayed a bell shape, with inhibition ratio of 24% only for m-Nis 2.5 mg.kg-1. The effect of verapamil (12.5 mg.kg-1, p.o., bid) was a little better than that of m-Nis. The intracellular VCO in medial smooth muscle cells of aorta were remarkably inhibited by m-Nis (2.5 mg.kg-1), with inhibition ratios of 72% for cytoplasm and 76% for mitochondrion. The calcium accumulation in nucleus was reduced to a lesser degree than those in cytoplasm and mitochondrion. CONCLUSION: As for aorta in VCO rats, m-Nis mainly had conspicuous inhibition on intracellular VCO in medial smooth muscle cells, particularly in cytoplasm and mitochondrion, but with little effect on extracellular calcium deposition at tissue level.

Animals↗
PubMed1995

Mch3, a novel human apoptotic cysteine protease highly related to CPP32.

Recent evidence suggests that mammalian cysteine proteases related to Caenorhabditis elegans CED-3 are key components of mammalian programmed cell death or apoptosis. We have shown recently that the CPP32 and Mch2 alpha cysteine proteases cleave the apoptotic markers poly(ADP-ribose) polymerase (PARP) and lamins, respectively. Here we report the cloning of a new Ced-3/interleukin 1 beta-converting enzyme-related gene, designated Mch3, that encodes a protein with the highest degree of homology to CPP32 compared to other family members. An alternatively spliced isoform, named Mch3 beta, was also identified. Bacterially expressed recombinant Mch3 has intrinsic autocatalytic/autoactivation activity. The specific activity of Mch3 alpha toward the peptide substrate DEVD-7-amino-4-methylcoumarin and PARP resembles that of CPP32. Like interleukin 1 beta-converting enzyme and CPP32, the active Mch3 alpha is made of two subunits derived from a precursor (proMch3 alpha). It was of interest that recombinant CPP32-p17 subunit can form an active heteromeric enzyme complex with recombinant Mch3 alpha-p12 subunit and vice versa, as determined by the ability of the heteromeric complexes to induce apoptosis in Sf9 cells. These data suggest that proMch3 alpha and proCPP32 can interact to form an active Mch3 alpha/CPP32 heteromeric complex. We also provide evidence that CPP32 can efficiently cleave proMch3 alpha, but not the opposite, suggesting that Mch3 alpha activation in vivo may depend in part on CPP32 activity. The high degree of conservation in structure and specific activity and the coexistence of Mch3 alpha and CPP32 in the same cell suggests that the PARP cleavage activity observed during apoptosis cannot solely be attributed to CPP32 but could also be an activity of Mch3 alpha.

Alternative Splicing↗
PubMed1995

Sex chromosome complement and developmental diversity in pre-and post-hatching porcine embryos.

To examine sex and development relationships in porcine embryos in early gestation, 10 gilts were killed on Day 4, 5, or 6 post mating (first day of standing estrus = Day 0). Embryos recovered immediately after slaughter were cultured in Medium 199 with colcemid (0.05mug/ml), fixed on slides, and stained with 4% Giemsa. The number of cells in each specimen was counted from the slides, and, whenever cell dispersion allowed, sex was determined by presence or absence of the Y-chromosome in at least 2 spreads from each embryo. Three gilts slaughtered on Day 4 yielded 2- and 4-cell stage embryos (n = 38), but no data on sex could be obtained due to lack of mitosis or readable metaphase spreads. Three Day 5 litters had individual specimens ranging from 8 to 14 cells (n = 8), 32 to 64 cells (n = 10), and 13 to 31 cells (n = 11), with the sex determined in 15 of these. Cell numbers ranged from 18 to 165 (n = 14), 16 to 32 (n = 9), 36 to 82 (n = 12), and 16 to 30 (n = 9) in the 4 gilts slaughtered on Day 6, with the sex determined in 26 of these. Embryos within each litter were divided into low, medium and high cell numbers by 3 equal divisions of the range of cell numbers. Three Day-5 embryos and 1 Day-6 embryo were lost during preparation; neither the cell numbers nor the sex could be determined in 4 Day-5 and in 3 Day-6 embryos. The overall sex ratio approximated 1:1, but on Day 5, the ratios for males to females were 0:5, 1:3 and 6:0 for the low, medium and high cell number groups, respectively. Embryos of undetermined sex in these same groups numbered 3, 1 and 3, respectively. On Day 6 the distribution was 1:11, 4:2 and 8:0 in favor of the males, while embryos of undetermined sex in the low, medium and high cell number groups numbered 5, 7 and 2, respectively. Chi-square analysis of the combined Day-5 and Day-6 results indicated the presence of significantly more females among embryos with low cell numbers and more males in the high cell number group (P < 0.01).

Journal Article↗
PubMed1995

Genetic immunization against herpes simplex virus. Protection is mediated by CD4+ T lymphocytes.

Plasmid DNA encoding proteins represent a convenient novel approach to vaccination. We have investigated this "genetic immunization" approach as a means to protect against herpes simplex virus (HSV) infection using a mouse zosteriform model that mimics several aspects of reactivated HSV infection of humans. After i.m. immunization with plasmid DNA-encoding glycoprotein B (gB), (pc-gB), 80% of BALB/c mice were completely protected and lesions were delayed in the remaining animals. Upon pc-gB vaccination, the animals developed both gB- and HSV-specific IgG Ab response and the isotype examination revealed a predominance of IgG2a. These mice also have low levels (1/16) of HSV-neutralizing Abs. Immune splenocytes obtained from pc-gB-immunized mice, when restimulated in vitro with HSV resulted in production of type 1 cytokines. Evidence for CD(8+)-mediated cytotoxic T lymphocyte response was equivocal. Protection could be adoptively transferred to nude mice recipients by CD4+ T cells from pc-gB-immunized mice but not by CD8+ T cells. Our results demonstrate that genetic immunization is a potent means of inducing protection against HSV and that the mechanism of immunity responsible for clearing virus from cutaneous sites is principally by CD4+ T cells. It is likely that these cells are Th1 cells because type 1 cytokines were the major cytokines detected upon in vitro Ag stimulation.

Animals↗
PubMed1995

An evaluation of numerical integration algorithms for the estimation of the area under the curve (AUC) in pharmacokinetic studies.

Six numerical integration algorithms based on linear and log trapezoidal methods as well as four cubic-spline methods were proposed for estimation of area under the curve (AUC). These six different algorithms were implemented using IMSL/IDL command language and evaluated using data simulated under five different dosing conditions and two different sampling conditions. Comparisons between AUC estimations using these six different algorithms and the theoretical results were made in terms of both overall AUC values and the superimposability of the concentration-time profiles. In well designed studies with ample data points, the algorithm based on IMSL/IDL function CSSHAPE with concavity preservation gave the best performance. In contrast, when the frequency of blood collection was limited, the algorithm based on the log trapezoidal rule proved to be stable with reasonable accuracy, and is recommended as the practical method for numerical interpolation and integration in pharmacokinetic studies. Algorithms based on the combination of the log trapezoidal rule and cubic-spline methods using IMSL/IDL function CSSHAPE can be developed to enhance overall performance.

Algorithms↗
PubMed1995

Antiviral action of interferon-beta on Newcastle disease virus: selectivity to the hemagglutinin-neuraminidase gene expression.

Interferon-beta (IFN-beta) strongly inhibited the expression of the hemagglutinin-neuraminidase (HN) gene of Newcastle disease virus (NDV), a paramyxovirus, in HeLa cells under the conditions where it did not affect the expression of the four upstream genes encoding the nucleocapsid protein, phosphoprotein, membrane protein and fusion protein. Even the downstream gene, encoding the large protein as well as the genome replication, appeared to be less susceptible to IFN-beta than the HN gene. This selective action of IFN-beta did not appear to be attributable to its well characterized antiviral mechanisms such as acceleration of RNA decay and translation inhibition. No similar down-regulation of a particular gene expression was found with another paramyxovirus, Sendai virus, or with a rhabdovirus, vesicular stomatitis virus, or seems to have been reported previously with any negative-strand RNA viruses. This new effect of IFN-beta thus suggests gene expression mechanism unique to NDV and may further lead to the discovery of a novel biochemical effect of IFN-beta.

Animals↗
PubMed1995

Adhesion of denture tooth porcelain to heat-polymerized denture resin.

Use of porcelain denture teeth may be desirable in many clinical situations, including implant-supported prostheses. However, lack of space because of frameworks often precludes the use of conventional retention by diatorics and pins. Adhesion of porcelain denture teeth to denture resin could also stiffen and possibly strengthen dentures and decrease stain ingress between porcelain teeth and resin denture bases. Unlike previous studies that investigated the bond between conventional feldspathic metal-ceramic porcelain and bis-GMA based composite resin, this study investigated adhesion of denture tooth porcelain to polymethyl methacrylate (PMMA). High-energy air abrasion, hydrofluoric acid etching, and the use of a general purpose bonding agent resulted in an improved bond strength of heat-cured denture PMMA bonded to denture tooth porcelain. Silane coating did not improve bond strengths, and conventional air abrasion was no more effective than polishing with 600-grit silicon carbide. Storage in water and artificial aging substantially decreased bond strengths. The strongest bond strengths were achieved by a high-energy-abrasion + etching + multi-purpose bonding-agent treatment, but a simpler etching + multiple-purpose bonding-agent treatment also produced reliable results. A laboratory technique was suggested. The role of surface treatment in the mechanism of adhesion was examined with scanning electron microscopy. High-energy abrasion produced a slightly more detailed initial topography than conventional air abrasion, but after etching, the high-energy topography became much more detailed. Surface topography alone did not account for all differences found.

Analysis of Variance↗
PubMed1995

In vivo marginal adaptation of cast crowns luted with different cements.

Large marginal crown discrepancies are deleterious. Although previous studies have examined casting seating in vitro, few have evaluated the effects of different luting cements on in vivo seating. Hence this in vivo study compared marginal discrepancies created by different cements on cast crowns. Tooth preparations were completed according to acceptable procedures on previously intact human molars that were severely periodontally compromised and scheduled for extraction. Castings were made by conventional techniques. The castings were randomly assigned to the following luting agents: zinc phosphate cement, resin-modified glass-ionomer cement, and the same resin-modified glass-ionomer cement with a dentinal bonding agent. After 6 months the teeth were carefully extracted, embedded, and sectioned, and vertical and horizontal discrepancies were measured. Analysis of variance revealed that all cements resulted in similar discrepancies. Vertical discrepancies were considerably greater than horizontal discrepancies, and the distributions of marginal discrepancies were skewed towards upper ranges.

Analysis of Variance↗