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Biomedical subjects

Z Yu

Publications and source records attributed to Z Yu.

At least 253 records · Page 14Linked to original sources
PubMed1997

Effects of superoxide anion, B(alpha)P and TPA on the membrane fluidity of NIH3T3 cells.

The membrane fluidity of NIH3T3 cells treated with low and high concentration of cell stimulatives (extracellular generated superoxide anion(O2-.),12-O-tetra-decanoyl-phorbol-13-acetate(TPA), and benzo(alpha)-pyrene[B(alpha)P]) was investigated by means of fluorescence labels 1,6-diphenyl-1,3,5 hexatriene (DPH) and N-(3-pyrene) maleimide (N(3p)M). The high concentration of O2-., TPA, B(alpha)P greatly increased the fluidity of cell membrane lipid domain. No changes of the florescence polarization of DPH was found in membrane lipid domain treated with low concentration of O2-., TPA, and B(alpha)P. However, decrease in the fluoresence polarization of N(3p)M on the cell membrane protein domain damaged by low concentration of cell stimulatives was observed, showing that these treatment could influence the conformation of membrane protein. The possible relationship between the changes of the conformation of membrane protein and the cell transformation and its carcinogenic machenisms were discussed.

3T3 Cells↗
PubMed1997

[Study on the relationship between intratumor microvessel density and neck metastasis of laryngeal and hypopharyngeal squamous cell carcinomas].

Sixty-one laryngeal and hypopharyngeal squamous cell, carcinoma (LC, HPC) tissue slides were immunochemically stained using LSAB method to study epithelium cells. The results demonstrated that (1) intratumor microvessel density (ITMD) in LC and HPC group was higher than that of the benign group (P < 0.05). ITMD was higher in the subgroup of LC and HPC with positive lymph node positive than that with negative lymph nodes. This result suggest that ITMD is relevant not only to the nature of the tumor, but also to lymph node metastasis. The level of ITMD is an important predictive sign of metastasis. (2) The relationship between ITMD and the clinical staging had no statistic significance (P > 0.05). (3) The analysis on the relationship between ITMD and pathologic differentiation indicated that the level of ITMD raised gradually with the lowering of the pathologic differentiation.

Carcinoma, Squamous Cell↗
PubMed1997

[Effects of yizhi pills on memory, superoxide dismutase and malondialdehyde of brain and immunity in mice].

Passive avoidance tests have shown that Yizhi Pills (YZ) markedly improve the memory of normal mice at a dose of 100 mg/kg after oral administration for fifteen days, and significantly reverse the scopolamine, NaNO2 and EtOH-induced disruptions of memory retention in mice at doses of 100, 200, 500 mg/kg after oral administration for five days. In aged mice induced by D-galactose, YZ also significantly improve the impaired memory, increase the activity of SOD and decrease the content of MDA in brain. All these effects were observed at doses of 200, 500 mg/kg after oral administration for forty-one days. YZ significantly promote blood carbon particle clearance, enhance hemolysin antibody in immunodepressed mice induced by cyclophosphamide, and increase earswelling in immunodepressed mice induced by prednisolonum.

Animals↗
PubMed1997

[Pharmacological study on the compatibility of cortex Cinnamomi with Halloysitum Rubrum].

The decoction of Cortex Cinnamomi (CC, 1 g/kg p.o.) and Halloysitum Rubrum (HR, 3 g/kg p.o.) or the combination of the two drugs (4 g/kg p.o., CC 1 g/kg, HR 3 g/kg) could antagonize the diarrhea caused by p.o. water ex tract of Radix et Rhizoma Rhei in mice; and inhibit the platelet aggregation induced by ADP in vitro. Meanwhile, the effect of the combination of the two drugs was not different from that of each single one. In addition, CC was able to inhibit the spontaneous movement of intestine in situ and showed an analgesic effect (hot-plate method) in mice; HR was ineffective in these aspects and did not reduce the effect of CC. CC(20 g/kg p.o., i.p. or i.v.) exhibited very strong toxicity in mice, while HR(60 g/kg p.o., i.p. or i.v.) was nontoxic. When the two drugs were used together, the toxicity was markedly reduced.

Aluminum Silicates↗
PubMed1997

[Adaptation of myocardial function to simulated weightlessness].

To observe the changes in myocardial function and calcium ion release of sarcoplasmic reticulum in rats under simulated weightlessness, 24 Sprague-Dawley male rats were divided into control (CON), 8 week tail-suspension (SUS) and recovery for 2 weeks (RE) groups. The results showed that there was no change in resting tension of myocardial twitch in SUS. While the developed tension (DT) of myocardial twitch significantly decreased in SUS as compared with CON. The time to peak tension (TPT) and time to half relaxation (T1/2R) of myocardial twitch were prolonged in SUS. DT, TPT and T1/2R recovered to their corresponding control values after 2 w of recovery from tail-suspension. The early recovery curve of force-interval relation in SUS was in a higher position over that of CON, but the rest potentiation and rest depression curve was positioned under that of CON. These results suggested that there might be an adaptative change in myocardial function in medium- or long-term tail-suspended rats while 8 w tail-suspension reduces calcium ion release from cardiac sarcoplasmic reticulum in rats.

Adaptation, Physiological↗
PubMed1997

[Textual research on Wei Yuhuang's life].

Wei was not only a noted doctor, but also a poet, who made friends with contemporary famous scholars. Based on these scholar's writings, this author maintains that Wei's sobriquet was not "Yuhuang", but rather "Yuheng"; and his date of birth was 1719, not in 1722; He had lived a life of 54 years old, not 50. Wei was born in Guangdong, later came to Hangzhou at 12 years old. His life was full of frustrations. The article makes a textural research into his tracks, means of making a living, to his places of activities especially in Hangzhou.

China↗
PubMed1997

[Comparison on pharmacological functions of pheretima].

Hot water extraction of Pheretima have marked actions in antipyretic, hypotensive, antiasthmatic and diuresis. Among them Guang-Pheretima and Hu-Pheretima are stronger than Tu-Pheretima in antipyretic. The difference of the intensity of Pheretima in the other actions is not obvious.

Animals↗
PubMed1997

[Protective effect of paeonol on repeated cerebral ischemia in rats].

Protcective effect of paeonol was observed in the repeated cerebral ischemia-reperfusion model in rats. Paeonol (100, 50 mg/kg x 7 d i.p.) could inhibit the increase of Ca2+, the decrease of superoxide dimutase (SOD) activity and the content of malondialdehyde (MDA), improve Ca(2+)-ATPase activity in ischemia brain tissue. The results showed that paeonol could protect cerebral ischemia by inhibiting accumulation of Ca2+ and production of oxygen free radical.

Acetophenones↗
PubMed1997

[Virological and clinical features of patients with sporadic hepatitis C].

In this study, the transmission route in 16 sporadic hepatitis C (SHC) patients was investigated. Three of them were surgeons who had often had occupational needlestick accidents, another 3 had close household contact with their spouses who had been diagnosed as chronic posttransfusion viral hepatitis C (PTHC), and the remaining 5 had potential parenteral exposure such as tooth extraction, injection or inoculation and so on. Five patients with SHC didn't have such history, their transmission route was not determined. Our result showed a lower viremia level in patients with SHC when compared to PTHC patients (the serum dilutions for HCV RNA detection was 10-100 times in the former and 100-10000 times in the latter. P<0.01). Only 1 patient with SHC was anti-HCV positive. Comparing to PTHC, the patients with SHC in our study had milder liver demage and lower ALT levels, and most of them (10/16) were symptomless.

Adult↗
PubMed1997

[Reversal of drug resistance in multidrug resistant tumor cells by an oligomer complementary to the MDR1 gene].

OBJECTIVE: To overcome the multidrug resistance (MDR) in tumor cells. METHODS: Human drug resistant cell line KB-8-5 was transfected with a synthetic oligodeoxynucleotide complementary to the 5' end region of MDR1 gene (ODN). In vitro drug sensitivity was measured by MTT assay. Intracellular drug concentration was assessed by flow cytometric analysis and expression of P-glycoprotein (Pgp) was determined by immunohistochemistry method. RESULTS: The administration of ODN for 72 hours increased daunorubicin (DNR) accumulation and decreased Pgp expression in KB-8-5 cells. Incomplete reversal of MDR in the KB-8-5 cells was observed when lipofectin was used to deliver ODN to the cells. Lipofectin enhanced the reversing activity, and approximately 74.43% of the cells lost their resistance to DNR. CONCLUSION: ODN circumvents resistance in the KB-8-5 cells may be ascribed to the reduced expression of Pgp in the cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

[Comparative study on the lysis of leukemia cells by IL-2 activated bone marrow and cord blood].

OBJECTIVE: To explore the antitumor activity of IL-2 activated bone marrow (ABM) and cord blood (ACB) mononuclear cells. METHODS: The antitumor activity of ABM and ACB mononuclear cells to the K562 (NK sensitive) and HL-60 (NK resistant) cells was studied by 3H-TdR release assay and semisolid culture method. The progenitor cell activity (PCA) of ABM and ACB was also assayed. RESULTS: After coculturing for 24 hrs with IL-2, the tumor-killing activities of ABM to K562 cells and to HL-60 cells were identical, while the activity of ACB to K562 cells was higher than that to HL-60 cells. After 72 hr coculturing, the activities of ABM to K562 and HL-60 cells were still higher than that of ACB. The optimum conditions for the activation of ABM and ACB were 1000U/ml IL-2, 1 x 10(6)/ml cells, 100 : 1 effector to target ratio and 72 hr culturing. PCA was not affected after IL-2 activation, while the immunophenotypic markers changed greatly. TNFalpha and IL-6 were detectable after culturing for 24 hrs, and went higher at 72 hrs. Large granular lymphocytes were generated both in cord blood and bone marrow after 24 hr culturing with IL-2. CONCLUSION: Both bone marrow and cord blood could be activated by IL-2 and gained cytotoxic effects, but the cytotoxicity of ACB was slightly lower than that of ABM under the same culturing condition. The mechanism of cytotoxicity might be cell mediated cytotoxicity and releasing of cytokines such as TNFalpha and IL-6.

Biomarkers↗
PubMed1997

[A laplace transform method for analysis of fluorescence dynamics].

A Laplace transform formula is developed for analysis of a multi-exponential fluorescence dynamic process. A dynamic spectrum function is introduced, calculation of which directly yields parameters of the corresponding dynamic process. The formula is applied to analyze fluorescence dynamics of beta subunit from R-phycoerythrin. It is demonstrated that electronic excited-states of the biomolecular system exhibit two exponential decay processes, the faster of which relates to excitation equilibrium among chromophores, and the slower to radiative relaxation of the chromophores.

English Abstract↗
PubMed1997

Characterization of proflavine metabolites in rainbow trout.

Proflavine (3,6-diaminoacridine) has potential for use as an antiinfective in fish, and its metabolism by rainbow trout was therefore studied. Fourteen hours after intraarterial bolus administration of 10 mg/kg of proflavine, three metabolites were found in liver and bile, and one metabolite was found in plasma using reversed-phase HPLC with UV detection at 262 nm. Treatment with hydrochloric acid converted the three metabolites to proflavine, which suggested that the metabolites were proflavine conjugates. Treatment with beta-glucuronidase and saccharic acid 1,4-lactone, a specific beta-glucuronidase inhibitor, revealed that two metabolites were proflavine glucuronides. For determination of UV-VIS absorption and mass spectra, HPLC-purified metabolites were isolated from liver. Data from these experiments suggested that the proflavine metabolites were 3-N-glucuronosyl proflavine (PG), 3-N-glucuronosyl,6-N-acetyl proflavine (APG), and 3-N-acetylproflavine (AP). The identities of the metabolites were verified by chemical synthesis. When synthetic PG and AP were compared with the two metabolites isolated from trout, they had the same molecular weight as determined by matrix-assisted, laser desorption ionization, time-of-flight MS. In addition, they coeluted on HPLC under different mobile phase conditions. Finally, the in vitro incubation with liver subcellular preparations confirmed this characterization and provided the evidence that APG can be formed by glucuronidation of AP or acetylation of PG.

Animals↗
PubMed1997

Effect of fit adjustment on CEREC CAD-CAM veneers.

PURPOSE: To measure and compare the adaptation of CEREC CAD-CAM porcelain veneers with and without fit adjustment. MATERIALS AND METHODS: Two groups of porcelain veneers were fabricated using the CEREC CAD-CAM technique for standardized preparations on 10 artificial teeth. Mesial preparation contacts were broken, but distal contacts remained intact. One group was adjusted using a disclosing spray to improve fit, another group made for the same teeth was not adjusted before cementation. The veneers were cemented in a standardized manner to their teeth. The veneers and their attached cement were retrieved, embedded in epoxy resin and sectioned twice to produce eight sections. Each section was measured at three defined points from the external surface inwards. RESULTS: Three-way ANOVA disclosed that fit adjustment was relatively ineffective (P approximately 0.05), but that measurement section location, measurement point location and their interaction significantly affected fit (P < 0.05). Restoration of the broken proximal contact, or simulated diastema closure did not compromise fit. Incisal margins ranked worst for fit. Surface measurement point locations ranked worse than internal points. The fit of these CEREC CAD-CAM veneers was not substantially different from previously published fit values for conventional porcelain veneers.

Acrylates↗
PubMed1997

The study of IL-1 beta, TNF-alpha, IL-6 gene expression and plasma levels on hemodialysis before and after dialyzer reuse.

OBJECTIVE: To investigate the biocompatibility of dialyzer reuse. METHODS: Twenty-two hemodialysis patients were randomized into cuprophan (CU, 7), polymethylmethacrylate (PMMA, 7) and polysulphone (PS, 8) membrane groups to observe IL-1 beta, TNF-alpha, IL-6 gene expression and their plasma levels by using themselves as control with enzyme-linked immunosorbent assay (ELISA), reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization. RESULTS: Plasma levels of interlukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) were 14.07 +/- 3.32 pg/ml, 67.41 +/- 19.79 pg/ml, 83.67 +/- 40.34 pg/ml; 12.80 +/- 3.01 pg/ml, 49.65 +/- 9.75 pg/ml, 33.36 +/- 12.14 pg/ml and 14.41 +/- 3.16 pg/ml, 80.56 +/- 23.22 pg/ml, 48.14 +/- 16.01 pg/ml, respectively, after patients dialyzed with CU, PMMA and PS membranes. Plasma cytokine levels decreased after reuse compared with those before reuse in each group. But no significant difference was found between them (P > 0.05); the levels of IL-1 beta, TNF-alpha, IL-6 gene expression after reuse were 5.61 +/- 0.33, 2.11 +/- 0.12, 5.04 +/- 0.19%; 2.43 +/- 0.19, 1.29 +/- 0.11, 3.48 +/- 0.20% and 2.48 +/- 0.20, 1.24 +/- 0.11, 3.22 +/- 0.20% respectively by in situ hybridization, and 0.92 +/- 0.07, 0.63 +/- 0.05, 0.53 +/- 0.05; 0.61 +/- 0.06, 0.47 +/- 0.04, 0.37 +/- 0.03 and 0.59 +/- 0.05, 0.44 +/- 0.04, 0.38 +/- 0.03 by RT-PCR, respectively. After reuse there was significant decrease as compared with that before reuse (P < 0.001, P < 0.005 and P < 0.05, respectively). CONCLUSIONS: This suggested reprocessing dialyzer with formaldehyde reduced cytokine release and gene expression in peripheral blood mononuclear cells and enhanced dialyzer biocompatibility. It would be beneficial to reduce the dialysis cost and may reduce the complication related to a long term hemodialysis.

Adult↗
PubMed1997

[An improved ISRA algorithm for ECT].

Image space reconstruction algorithm (ISRA) is a new kind of method for ECT reconstruction. Unlike the ML-EM algorithm which maximizes likelihood function of Possion distribution, ISRA searches for the minimum non-negative mean square solution. In this paper, an improved ISRA (IISRA) algorithm is proposed. A comparison between the algorithms (ISRA and IISRA) demonstrates that the result of IISRA is closer to the test image than that of ISRA. In addition, the IIRSA inherits some properties of ISRA such as convergence.

Algorithms↗