Biomedical subjects

Y Han

Publications and source records attributed to Y Han.

At least 181 records · Page 10Linked to original sources

PubMed1999

[Alterations of platelet membrane glycoproteins in patients with diabetes mellitus and their clinical significance].

OBJECTIVE: To investigate changes of platelet glycoproteins in patients with diabetes mellitus(DM) type II and their clinical significance. METHODS: Seventy DM patients and 28 normal individuals entered in this study. The platelet glycoproteins Ib, IIb, IIIa and P-selectin were analyzed by flow cytometry (FCM). Platelet surface P-selectin was measured by Immunoradiometric analysis (IRMA), and plasma P-selectin concentration by ELISA. RESULTS: On FCM, the P-selectin expression on platelets of patients with vascular diseases [(10.28 +/- 4.86)%] was higher than that of normal subjects [(3.75 +/- 1.83)%] (P < 0.01) and patients without vascular diseases [(4.25 +/- 2.29)%] (P < 0.01). Similar results were obtained using IRMA. Plasma P-selectin concentration in patients with vascular diseases [(6.18 +/- 3.20) ng/ml] was higher than that of control group [(3.43 +/- 1.56) ng/ml](P < 0.05) and that of patients without vascular diseases [(3.71 +/- 2.12) ng/ml] (P < 0.05). On the contrary, the platelet surface GP Ib expression in patients with vascular diseases [(86.35 +/- 11.00)%] was remarkably lower than that of normal subjects [(92.63 +/- 7.55)%] (P < 0.05), while platelet GP IIb and IIIa were not changed in any cases. CONCLUSION: The P-selectin levels in plasma and on platelet surface were increased while platelet membrane GP Ib was decreased in DM type II patients with vascular events.

Adult↗

PubMed1999

[Human hR24L gene is involved in DNA excision repair and recombination repair].

OBJECTIVE: To study the correction phenotype of temperature sensitive mutant rad24LR of S. cerevisiae and to clone wild human functional homologue. METHODS: The temperature sensitive mutant rad24LR was studied by complementation test. Transformation of rad24LR was performed with human cDNA expression library to screen for reversion phenotype. RESULTS: RAD24L can complement the radiation sensitive phenotype of the mutation. Its homologue of human cDNA was cloned by screening transformed rad24LR with human expression library for reversion phenotype. CONCLUSION: Human DNA repair gene hR24L was successfully cloned in this study. The product hR24L is involved in both DNA excision repair and recombination repair.

Cloning, Molecular↗

PubMed1999

[Comparative study on therapeutic effects of gandou tablet I and dimercaptosuccinate acid in treating Wilson disease].

OBJECTIVE: To compare the effects of Gandou I (GD, a Chinese herbal preparation) and dimercaptosuccinate acid (DMSA) in treating Wilson disease (WD). METHODS: Ninety-four patients with WD were divided into 2 groups, 32 cases in the GD group and 62 in the DMSA group, they were treated with GD and DMSA respectively. The therapeutic course was 4 weeks for both groups. Modified Goldstein's Degree was adopted to evaluate the clinical effect. RESULTS: The total effective rate of the GD group was 71.9%, which was similar to that of the DMSA group (77.4%, P > 0.05). But the adverse reaction occurred in the latter group was more than that in the former. CONCLUSION: GD is a low toxic and highly effective drug for long-term treatment of WD.

Adolescent↗

PubMed1999

[Transfection of articular chondrocytes with PcNDA3-hBMP3 and its stable expression].

OBJECTIVE: To explore the possibility of stable expression of PcDNA3-hBMP3 in cultured articular chondrocytes of rabbit. METHODS: PcDNA3-hBMP3 was constructed using gene clone technique and recombined DNA technique. With the help of profectamine, the cultured articular chondrocytes were transfected with PcDNA3-hBMP3, and the evidence of successfully stable transfection in these cells could be obtained by positive northern blot. RESULTS: The cultured articular chondrocytes of rabbits seemed to be polygonal, and its logarithmic growth phase was 2 - 4 days after cell inoculation. The two fragments cut from PcDNA3-hBMP3 by EcoR I and Xba I represented 5.4 kb and 1.4 kb by electrophoresis, which were confirmed to be the carrier and the fragment inserted originally, indicating that the construction of PcDNA3-hBMP3 was successful. The RNA extracted from cultured chondrocytes was screened for 4 weeks by G418 hibrided with the fragment cut from hBMP3 positively. CONCLUSIONS: With the help of profectamine, the cultured articular chondrocytes can be transfected by recombined gene of PcDNA3-hBMP3 successfully, and their stable expression at 4 weeks after transfection is obtained.

Animals↗

PubMed1999

[Combined use of rhBMP2/BCB and free periosteum in repairing segmental defects in radii of rabbits].

OBJECTIVE: To study the efficacy of combined use of rhBMP2/BCBand free periosteal graft in repairing segmental bony defects. METHODS: A new grafting material (rhBMP2/BCB) was made by combining recombinant human BMP2 (rhBMP2) and an antigen-free bovine cancellous bone (BCB) as a carrier. rhBMP2/BCB was used alone in conjunction with free periosteal graft to repair a 1.5 cm defect in the radius of the rabbit. The defect-repairing capability for each of the treatment modalities was assessed radiographically, biomechanically, and by densitometry and histological studies. RESULTS: rhBMP2/BCB used alone was capable of healing the defect in large by 16 weeks, with a similar repair process and mechanism seen with RBX. Combined use of rhBMP2/BCB and free periosteal graft was superior in terms of increased amount and quality of the new bone formed at the early stage of the repair process (within 12 weeks) to rhBMP2/BCB used in isolation, with the defect basically healed by 12 weeks. CONCLUSIONS: Both methods are effective in repairing segmental bony defects, with rhBMP2/BCB used in conjunction with free periosteal graft being most preferred, considering the satisfactory osteogenesis, osteoconduction and osteoinduction.

Animals↗

PubMed1999

[Component in diphtheria-pertussis-tetanus-hepatitis B vaccine].

OBJECTIVE: To study immunogenecity of yeast-derived recombinant hepatitis B (YHB) component in diphtheria-pertussis-tetanus-YHB vaccine (DPTw-YHB). METHODS: Immunogenecity of tetra-valent DTPw-YHB vaccine and mono-valent recombinant YHB vaccine, and that of the tetra-valent vaccine with varied YHB component were compared. The efficiency and stability of recombinant YHB in the tetra-valent vaccine stored at 2 - 8 degrees C for 18 months were determined. RESULTS: The efficiency of recombinant YHB in the tetra-valent vaccine enhanced significantly in mice, as compared with that of mono-valent recombinant YHB vaccine, with an average mouse ED(50) of 1:2.0 - 1:3.1. There was no significant difference in efficiency of the tetra-valent vaccine with varied recombinant YHB component. Recombinant YHBin the DPTw-YHB tetra-valent vaccine still kept good stability stored at 2 - 8 degrees C for 18 months. CONCLUSION: Recombinant YHB in the tetra-valent vaccine was more immunogenic than the mono-valent YHB vaccine. No interference and inhibition of DPTw to recombinant YHB was found, indicating good compatibility between DPTw and YHB.

Animals↗

PubMed1999

[Studies on identification of yinchaihu by UV and IR].

OBJECTIVE: To study the identification of nine species of Yinchaihu derived from four genera of Caryophyllaceae, namely, Stellaria dichotoma var. lanceolata, St. dichotoma var. dichotoma, Arenaria juncea, A. capillaris var. glandulifera, Silene fortunei, Si. jenisseensis, Gypsophila pacifica, G. oldhamiana and G. licentiana. METHOD: UV and IR of alcohol extraction. RESULTS: The UV and IR spectra of these 9 plant roots have some difference. CONCLUSION: St. dichotoma var. lanceolata specified in the Chinese Pharmacopoeia can be distinguished from the other plants and all these 4 genera can be differentiated from one another by both UV and first derivative spectra. The genus Stellaria can be identified from the other 3 genera by IR.

Caryophyllaceae↗

PubMed1999

[Determination of resveratrol in grape wine by high performance liquid chromatography].

Resveratrol is a microactive factor for preventing human cancer. A reversed phase high performance liquid chromatographic method for the determination of resveratrol in grape wine was developed. Samples were extrated by ethyl acetate and washed with 3% NaHCO3; after dehydrated with Na2SO4 and dried in vacunm at 40 degrees C, dissovled in acetonitrile. The conditions of HPLC analysis were as follows: the maximum absorptions of trans-resveratrol and cis-resveratrol were at 306 nm and 280 nm respectively. Separation was achieved by the use of mu-Bondapak C18 column (3.9 mm x 300 mm). The mobile phase was V(acetonitrile):V(water) = 40:60. The retention times of trans- and cis-resveratrol were 7.7 min and 8.9 min respectively. The recovery rates were 90.0%-97.8% and the CV was 3.3%. Detection limit was 10 micrograms/L. Eleven kinds of red and white grape wine made in China were detected. All of them contained resveratrol, but the quantity, from 10.0 to 920.0 micrograms/L, were quite different.

Anticarcinogenic Agents↗

PubMed1999

Suppressive effect of carotenoids on the luminol dependent chemiluminescence of the stimulated rat macrophages.

Rat macrophages stimulated by phorbol 12-myristate 13-acetate (PMA) produced significant chemiluminescence in luminol. Carotenoids suppressed the luminol-dependent chemiluminescence at the beginning and after two minutes of the stimulation. Canthaxanthin and bixin had higher suppressive activity that beta-carotene and lutein. The measurement of the absorption spectra of carotenoids showed that the absorption by carotenoids was diminished during the stimulation of macrophages. The results suggest that the suppressive effect of carotenoids may be due to their scavenging the reactive oxygen metabolites released by macrophages.

Animals↗

PubMed1999

[Spectroscopic assay, chemical modification and activity of three kinds of polyoses].

Infrared spectra and nuclear magnetic resonance spectra of chitosan, pachyman and amorphalls mannan were studied. The difference among the infrared spectra of chitosan under different conditions was disscused. The modification of Methylolation of the three kinds of polyoses was made and the relationship between the chemical modification and the antitumor activity was also studied.

Antineoplastic Agents↗

PubMed1998

[Identification of a mutation hotspot in exon 8 of Wilson's disease gene by cycle sequencing].

OBJECTIVE: To screen for mutation hotspot of Wilson's disease (WD) gene in Chinese. METHODS: Cycle sequencing was used to detect mutation in exon 8 of WD gene in 30 patients with WD. RESULTS: The same missense mutation, Arg778Leu, was identified in 14 WD patients, four of which were homozygous and the others were heterozygous for this mutation. The frequency of this mutation was 30%. CONCLUSION: The codon 778(CGG-->CTG) of exon 8 in WD gene was one of mutation hotspots in Chinese.

Adolescent↗

PubMed1998

Effect of carotenoids on the respiratory burst of rat peritoneal macrophages.

The effect of four carotenoids (beta-carotene, lutein, bixin and canthaxanthin) on the respiratory burst of rat peritoneal macrophages was investigated. The results obtained showed that carotenoids suppressed the luminol-dependent chemiluminescence generated from PMA-stimulated macrophages at the beginning and after 2 min of the stimulation. Canthaxanthin and bixin had higher suppressive activity than beta-carotene and lutein. The changes in absorption spectra of carotenoids showed that the absorption by carotenoids was diminished during the stimulation of macrophages by PMA and their absorption peaks were either further diminished or blue-shifted after addition of L-arginine to the system, indicating that the carotenoids were consumed and converted to new compounds during the two processes. By using cell-free systems, it was found that carotenoids could scavenge superoxide anion generated by xanthine/xanthine oxidase system. Their ability to scavenge superoxide anion decreased in the order of canthaxanthin > bixin > lutein > beta-carotene. Canthaxanthin also showed the scavenging effect on superoxide anion generated from irradiation of riboflavin. The hydroxyl radical scavenging activity of carotenoids was investigated in the reaction system of Fe2+ and H2O2. There was little difference among their activities. The reaction between carotenoids and nitric oxide led to the decreasing absorption between 400 and 540 nm and the concomitant appearance of the new absorption peaks between 330 and 395 nm. Bleaching of beta-carotene, bixin and canthaxanthin by peroxynitrite resulted in the increasing absorption between 290 and 365 nm and the diminishing absorption between 400 and 500 nm. But the increasing absorption between 280 and 490 nm was observed in bleaching of lutein by peroxynitrite. Carotenoids inhibited thiobarbituric acid-reactive substance (TBARS) formation in AAPH-induced lipid peroxidation of PC liposomes in air. The results suggest that the suppressive effect of carotenoids on the respiratory burst of macrophages may be just a way by which carotenoids in vivo protect host cells and tissues from harmful effects of oxygen metabolites overproduced by macrophages and enhance the generation of specific immune responses.

Animals↗

PubMed1998

Identification, localization, and modulation of neural networks for walking in the mudpuppy (Necturus maculatus) spinal cord.

We tested the hypothesis that the neural networks for walking in the mudpuppy can be divided into a flexor and an extensor center, each of which contains collections of interneurons localized in the vicinity of their motoneuron pools. Combining a battery of techniques, we identified and localized the elbow flexor center and its motoneuron pool in the C2 segment and the elbow extensor center and its motoneuron pool in the C3 segment. Rhythmic flexion or extension of the limb in isolation could be induced by continuous trains of current pulses of the C2 or C3 segments, respectively. Independent activation could also occur after application of glutamate receptor agonist NMDA. Part of segment C2 in isolation generated rhythmic elbow flexor bursts, whereas part of segment C3 in isolation generated rhythmic elbow extensor bursts. An isolated region spanning the C3 roots generated both flexor and extensor bursts. The step cycle was modulated in a phase-dependent manner by stimulation of the dorsal roots, the ventral roots, or either of the two centers. The effects of ventral root stimulation were removed by deafferentation to block reafferent input attributable to muscle contraction induced by the stimulation. We conclude that the neural networks for walking contain at least a flexor and an extensor generator that are localized in close apposition to the motoneuron pools, that the two centers can work independently despite the fact that there are reciprocal inhibitory interconnections between them, and that sensory input interacts with the spinal neural networks to reset the ongoing walking rhythm in a phase-dependent manner.

Animals↗

PubMed1998

Distances between the paclitaxel, colchicine, and exchangeable GTP binding sites on tubulin.

Distances between the paclitaxel, colchicine, and exchangeable GTP binding sites on tubulin polymers have been probed using fluorescence spectroscopy. Techniques for measuring fluorescence resonance energy transfer (FRET) between fluorescent or chromophoric ligands for each binding site were employed. 2-Debenzoyl-2-(m-aminobenzoyl)paclitaxel (2-AB-PT) was the fluorophore ligand for the paclitaxel binding site; thiocolchicine, allocolchicine, and MDL 27048 were probes for the colchicine site, and 2'(or 3')-O-(trinitrophenyl)guanosine 5'-triphosphate (TNP-GTP) was the fluorophore ligand for the exchangeable GTP site. The distance between the colchicine and paclitaxel binding sites was determined with two different acceptor ligands in the colchicine site. An average distance distribution of 17 A was found in both cases. Energy transfer between 2-AB-PT bound to the paclitaxel site and TNP-GTP (acceptor) bound to the exchangeable GTP site was observed in the polymer. The average distance distribution between the fluorophores was 16.0 A, but the half-width of the distribution was large (17.9 A), which indicates that energy transfer between more than one donor-acceptor pair occurred in the system. One interpretation of this result is that 2-AB-PT serves as an energy transfer donor for two GTP sites, one contained on the same subunit and one on an adjacent protofilament. No FRET was observed between ligands bound to the colchicine and exchangeable GTP sites, indicating that the result of colchicine binding on the GTP region of beta-tubulin is a long range, allosteric effect. The results from these experiments are interpreted in terms of known structural features of microtubules.

Animals↗

PubMed1998

Four-crystal camera at BSRF and its applications.

The four-crystal camera is one of the major items of equipment of the topography station at the Beijing Synchrotron Radiation Facility. The design and some applications of this camera are presented.

Journal Article↗

PubMed1998

The white-radiation dynamic topography experimental system at the BSRF.

A white-radiation dynamic topography experimental system has been established at the BSRF (Beijing Synchrotron Radiation Facility) and is now in operation. Each part of this system is described in this paper, with particular emphasis given to the PC-based online control system, the X-ray video-imaging system and the image-treatment system. Moreover, some of the experimental results, such as the phase transition of KNbO(3) nonlinear optical crystals and of blue bronze charge-density-wave material, are briefly presented.

Journal Article↗

PubMed1998

Protein kinases modulate two glycine currents in salamander retinal ganglion cells.

1. Protein kinase modulation of glycine-activated currents was examined in acutely dissociated ganglion cells from tiger salamander retina using whole-cell voltage-clamp techniques. 2. Glycine (100 microM) induced an outward chloride current in cells clamped at 0 mV. Co-application of 50 microM forskolin made the glycine-induced current more transient. The combination of forskolin and glycine reduced the later portion of current response without changing the initial peak amplitude. 3. 3-Isobutyl-1-methylxanthine (IBMX) or 8-bromoadenosine 3',5'-cyclic monophosphate (8-Br-cAMP) produced effects similar to those of forskolin. H-89, a protein kinase A (PKA) inhibitor, blocked the effect of forskolin. 4. A protein kinase C (PKC) activator, OAG (1-oleoyl-2-acetyl-sn-glycerol), also made the glycine response more transient. Unlike PKA analogues, OAG enhanced the glycine peak response without changing the glycine late response. OAG effects were blocked by 1 microM GF-109203X, a PKC inhibitor. 5. Nanomolar concentrations of strychnine selectively blocked the fast phase of the glycine current and reversed the effect of OAG, but not that of forskolin. Conversely, forskolin occluded the effect of 5,7-dichlorokynurenic acid, which selectively suppresses the late phase of the glycine current. The action of OAG was not blocked by 5,7-dichlorokynurenic acid. 6. Thus, through a differential modulation, both protein kinase A and C shorten the decay time of the glycine current. PKA suppresses the slow component, while PKC potentiates the fast component.

1-Methyl-3-isobutylxanthine↗

PubMed1998

Genetic analysis using genomic representations.

Analysis of the genetic changes in human tumors is often problematical because of the presence of normal stroma and the limited availability of pure tumor DNA. However, large amounts of highly reproducible "representations" of tumor and normal genomes can be made by PCR from nanogram amounts of restriction endonuclease cleaved DNA that has been ligated to oligonucleotide adaptors. We show here that representations are useful for many types of genetic analyses, including measuring relative gene copy number, loss of heterozygosity, and comparative genomic hybridization. Representations may be prepared even from sorted nuclei from fixed and archived tumor biopsies.

Blotting, Southern↗