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Biomedical subjects

H M Xie

Publications and source records attributed to H M Xie.

8 recordsLinked to original sources
PubMed2001

[A study on the effect of rare earth metal ions on fluorescence spectra of the tryptophan using fluorescence spectroscopy].

Rare earth metal ions and tryptophan form ion-association complex in basic medium. The complex causes fluorescence quenching of tryptophan. Fluorescence emission of tryptophan and quenching caused by rare earth metal ions both reach a climax in H3BO4-HAc-H3PO4-NaOH at pH 10 to 11, and all rare earth metal ions have the approximate effects on fluorescence quenching of tryptophan. The molecular mode of complex of rare earth metal ions and tryptophan has been founded and mechanism of fluorescence quenching has been studied in this paper.

Chelating Agents↗
PubMed2000

Alleviation of pre-exposure to low-dose 16O8+ ion on mouse testicular histological damage induced by subsequent high-dose irradiation.

The testes of the B6C3F1 hybrid strain mice were irradiated with 0.05 Gy of 16O8+ ion as the pre-exposure dose (D1), and were then irradiated with 2 Gy of 16O8+ ion as challenging radiation dose (D2) at 4 h after per-exposure. Testicular morphology was observed by light microscope at 35th day after radiation. The results showed that irradiation of mouse testes with 2 Gy of 16O8+ ion significantly impaired, mainly reduction of tubule diameter and decrease or loss of germ cells in various developing stages, especially spermatogenic elements. Pre-exposure to a low-dose (0.05 Gy) of 16O8+ ion significantly alleviated above mentioned damage on testicular morphology induced by subsequent a high-dose (2 Gy) radiation.

Animals↗
PubMed1999

Effects of 16O+6 ion irradiation on human sperm spontaneous chemiluminescence, motility, acrosome reaction and viability in vitro.

Effects of 16O+6 ion irradiation with different doses on human sperm spontaneous chemiluminescence (SCL), motility, acrosome reaction (AR) and viability were examined. Spermatozoa were irradiated with 0, 0.25, 0.5, 1, 2, 4, 8, 16, 32, or 64 Gy 16O+6 ion beam at the energy of 3.17 MeV/u. After irradiation, samples were analyzed by SCL measurement at 1, 2 and 3 h of incubation; motility was determined by the transmembrane migration method within 2 h of incubation; the percentage of AR and viability was evaluated by the triple-stain technique at 3.5 h of incubation. The results showed: sperm SCL was significantly increased with irradiation doses and the lowest effective dose was 0.5 Gy; compared with controls, the transmembrane migration ratio of spermatozoa progressively elevated with irradiation doses at 0.5, 1, and 2 Gy; the percentage of sperm AR markedly increased in 0.5-4 Gy irradiation and the optimal dose was 2 Gy, and then significant decreased with further increase of irradiation doses; the viability had no significant change within 0.25-8 Gy, but was progressively decreased at 16, 32 and 64 Gy. These data suggested that heavy ion at low doses increased motility and AR, whereas had deleterious effects at higher doses, which are associated with free radical reactions induced by heavy ion irradiation.

Acrosome Reaction↗
PubMed1998

Effects of pre-exposure of mouse testis with low-dose (16)O8+ ions or 60Co gamma-rays on sperm shape abnormalities, lipid peroxidation and superoxide dismutase (SOD) activity induced by subsequent high-dose irradiation.

PURPOSE: To investigate the effects of pre-exposure of mouse testis with low-doses of (16)O8+ ions or 60Co gamma-rays on sperm shape abnormalities, lipid peroxidation and superoxide dismutase (SOD) activity induced by subsequent high-dose irradiation. MATERIALS AND METHODS: Testes of the B6C3F1 hybrid strain mice were pre-irradiated with 0.05 Gy of (16)O8+ ions or 60Co gamma-rays and then after 4 h given a test irradiation with 2 Gy of the same radiation type. SOD activity and thiobarbituric acid reactive substances (TBARS) in the testes were determined by spectrophotometric and TBA methods respectively at 4 h after irradiation. Testis weight, sperm count and sperm morphology were analysed at day 35 after irradiation. RESULTS: Compared with controls, there was a significant increase in SOD activity and a significant decrease in TBARS level of pretreated testes. Testis weight loss, sperm count reduction and sperm abnormalities were significantly lower in the pretreated testes. The bioeffects of a 2 Gy dose of (16)O8+ ions relative to 60Co gamma-rays were 1.84 +/- 0.28 for testis weight, 1.22 +/- 0.25 for sperm count and 1.29 +/- 0.10 for sperm abnormalities. CONCLUSIONS: These data suggest that pre-exposure of testes with a low dose of heavy ions or gamma-rays renders the organ more resistant to subsequent high-dose irradiation. The increase of SOD activity and the decrease of lipid peroxidation levels induced by low-dose ionizing irradiation may be involved in this resistance. The effects with heavy ion irradiation were greater than with gamma-rays.

Animals↗
PubMed1991

An in vitro study on roughening of the metal surface with lost crystal salts to increase the metal-resin bond strength.

Good mechanical retention between metal and resin or luting agent can be obtained by roughening the metal surface with lost crystal salts. The relationship of metal-resin bond strength to the shape and size of the crystals was studied. The results indicated that cuboid crystal salts provided the best roughening among the tested crystal shapes (cube, irregular, spherical, and cuboid). There was no relationship between the tensile bond strength and the size of the crystals. Furthermore, the bending strength of metal coated with resin was improved by the roughening of the metal surface.

Acrylic Resins↗
PubMed1989

[A PM visible light-cured dental bonding agent].

In order to get a better adhesion, less tooth abrasion and a good marginal sealing, bonding agent was used in the composites restorations. PM visible light cured bonding agent containing coupling agent 4-META was made. Polyfunctional monomer was used as the resin matrix. CQ and PA were used as the initiator. The tensile bonding strength of this bondx286p4ent to enamel was 84.5 kg/cm2. The shear bonding strength of this bonding agent to enamel when used with visible light cured composites together was 317.3 kg/cm2, which was higher then the report in the recent literatures. PM visible light cured bonding agent got a satisfied clinical result.

Adhesiveness↗