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Biomedical subjects

Yu Zhao

Publications and source records attributed to Yu Zhao.

At least 145 records · Page 8Linked to original sources
PubMed2003

[Integrated evaluation on system reliability of a space metabolism simulation device].

OBJECTIVE: To define the lower confidence limit of the system reliability of the space metabolism simulation device by using the test data of the comprising units in their development phases. METHOD: A new method for defining the environmental conversion factors of failure times has been given basing on the AMSAA model, and the MTBF point evaluated values and lower confidence limits of the units were defined, at last, the lower confidence limit of the system reliability was obtained using L-M method. RESULT: The lower confidence limit of the system reliability under confidence level of 0.8 is 0.9281, which is consistent with the result obtained by the classic system reliability evaluation method. CONCLUSION: Integrated system reliability evaluation using the proposed method can well satisfy the need in engineering.

Equipment Design↗
PubMed2003

[Study on DNA methylation status of WT1 gene promoter in leukemia cell].

OBJECTIVE: To analyse the WT1 expression and its DNA methylation status of its promoter domain. METHOD: The expression of WT1 gene and its DNA methylation status were assayed in leukemia cell lines and normal peripheral blood mononuclear cells (PBMNC) by RT-PCR and MS-PCR. RESULTS: WT1 was overexpressed in HL60, K562 and KG1 leukemia cell lines, but not in U937 and PBMNC. Methylation of WT1 promoter was not observed in HL60 cells. CONCLUSION: DNA methylation of WT1 gene promotor did not inhibit its expression. Other mechanisms may appear to regulate the WT1 expression.

Cell Line, Tumor↗
PubMed2003

[Analysis of LRP15 Gene Expression Pattern and Its Expression in Leukemia Cells].

To explore the possible function of LRP15 gene in carcinogenesis and its significance in the classification and prognosis of leukemia, the expression pattern of LRP15 in normal tissues, tumor tissues and cell lines was detected with SAGE and gene expression database provided by NCBI and NCI respectively. RT-PCR was used to detect the expression of LRP15 in leukemia patients. The results showed that LRP15 was expressed in different tissues and tumor cell lines, the positive rate of LRP15 in immature blood cells was higher than that of mature blood cells and the positive rate of M(1), M(2) and M(3) was higher than that of other AML subtypes (P < 0.01), the expression of LRP15 in refractory leukemia was higher than that of de novo leukemia. The results suggest that LRP15 may play an important role in carcinogenesis, AML classification and acute leukemia prognosis.

Cell Line, Tumor↗
PubMed2003

[Relationship between human herpesvirus 6 infection and oral squamous cell carcinoma].

OBJECTIVE: To study the relationship between human herpesvirus 6 (HHV-6) and oral squamous cell carcinoma. METHODS: The serum anti-HHV-6 antibody titers from oral squamous cell carcinoma patients and control subjects were detected by indirect immunofluorescence assay. HHV-6 DNA in peripheral blood mononuclear cells from oral squamous cell carcinoma patients and control subjects was amplified by PCR with primers from sequence of HHV-6 and the specificity was confirmed by Southern-blot hybridization with an internal probe oligonucleotide. An immunohistochemical staining using rabbit anti-HHV-6 antibody was used to detect HHV-6 antigen in oral tumor tissues from oral squamous cell carcinoma patients. RESULTS: Significantly higher proportion of patients with oral carcinoma (16/16) had IgG antibody to HHV-6 in sera compared with those (12/16) in control subjects, and geometric mean titer of these two groups was 1:118 and 1:64 respectively (P less than 0.05). The detectable rate of HHV-6 DNA in peripheral blood mononuclear cells for the above groups was 10/16 and 6/16 respectively (P less than 0.05). HHV-6 antigens were positive in 9 out of 12 oral tumor cases and in only 2 out of 8 pericancerous tissues the difference between these two groups was also significant (P less than 0.05). CONCLUSION: These results demonstrated the frequent presence of HHV-6 in oral squamous cell carcinoma, therefore, HHV-6 possibly play a role in the pathogenesis of oral squamous cell carcinoma.

Antibodies, Viral↗
PubMed2002

The specificity of extracellular signal-regulated kinase 2 dephosphorylation by protein phosphatases.

The extracellular signal-regulated protein kinase 2 (ERK2) is the founding member of a family of mitogen-activated protein kinases (MAPKs) that are central components of signal transduction pathways for cell proliferation, stress responses, and differentiation. The MAPKs are unique among the Ser/Thr protein kinases in that they require both Thr and Tyr phosphorylation for full activation. The dual phosphorylation of Thr-183 and Tyr-185 in ERK2 is catalyzed by MAPK/ERK kinase 1 (MEK1). However, the identity and relative activity of protein phosphatases that inactivate ERK2 are less well established. In this study, we performed a kinetic analysis of ERK2 dephosphorylation by protein phosphatases using a continuous spectrophotometric enzyme-coupled assay that measures the inorganic phosphate produced in the reaction. Eleven different protein phosphatases, many previously suggested to be involved in ERK2 regulation, were compared, including tyrosine-specific phosphatases (PTP1B, CD45, and HePTP), dual specificity MAPK phosphatases (VHR, MKP3, and MKP5), and Ser/Thr protein phosphatases (PP1, PP2A, PP2B, PP2C alpha, and lambda PP). The results provide biochemical evidence that protein phosphatases display exquisite specificity in their substrate recognition and implicate HePTP, MKP3, and PP2A as ERK2 phosphatases. The fact that ERK2 inactivation could be carried out by multiple specific phosphatases shows that signals can be integrated into the pathway at the phosphatase level to determine the cellular response to external stimuli. Important insights into the roles of various protein phosphatases in ERK2 kinase signaling are obtained, and further analysis of the mechanism by which different protein phosphatases recognize and inactivate MAPKs will increase our understanding of how this kinase family is regulated.

Glutathione Transferase↗
PubMed2002

Syntheses of two cytotoxic sinapyl alcohol derivatives and isolation of four new related compounds from Ligularia nelumbifolia.

Phytochemical reinvestigation on Ligularia nelumbifolia afforded four novel sinapyl alcohol analogues named nelumols B-E (1-4) and three known sinapyl alcohol derivatives (5-7). Their structures were elucidated by NMR techniques. Total syntheses of cytotoxic geranyloxy sinapyl alcohol (6) and geranyloxy sinapyl aldehyde (7) were carried out via two different paths. The 4-O-benzyl-substituted analogues (20 and 27) as well as the 4-O-(2-methylbutenyl) derivatives (34 and 35) were also synthesized. The cytotoxicities of 6 and 7 were measured using A-549, HL-60, and KB cancer cell lines.

Alcohols↗
PubMed2002

Alternative method to improve the repair of the donor site of the anterolateral thigh flap.

The groin flap was designed to improve the conventional repair of the donor site of the anterolateral thigh flap. The modification method was applied successfully to cover the defects of donor sites of anterolateral thigh flaps in five patients. An ideal color match and a stable and completed composition for the donor sites were obtained. Little morbidity of the donor sites occurred. Cosmetic and functional rehabilitations of the donor sites were achieved. These results suggest the potential and novel method to improve the repair of the donor sites of anterolateral thigh flap.

Adolescent↗
PubMed2002

L-type Ca2+ channels in fetal and adult ovine cerebral arteries.

Recently, we reported that, whereas in cerebral arteries of the adult a majority of norepinephrine (NE)-induced increase in intracellular Ca2+ concentration ([Ca2+]i) comes from release of the sarcoplasmic reticulum (SR) Ca2+ stores, in the fetus the SR Ca2+ stores are relatively small, and NE-induced increase in [Ca2+]i results mainly from activation of plasma membrane L-type Ca2+ channels (20). In an effort to establish further the role of L-type Ca2+ channels in the developing cerebral arteries, we tested the hypothesis that, in the fetus, increased reliance on plasmalemmal L-type Ca2+ channels is mediated, in part, by increased L-type Ca2+ channel density. We used 3H-labeled (+)isopropyl-4-(2,1,3-benzoxadiazol-4-y1)-1,4-dihydro-(2,6-dimethyl-5-methoxycarbonyl)pyridine-3-carboxylate (PN200-110, isradipine) to measure L-type Ca2+ channel density (Bmax) in the cerebral arteries, common carotid artery (CCA), and descending aortae of fetal (approximately 140 gestation days), newborn (7-10 days), and adult sheep. In the cerebral and common carotid arteries, B(max) values (fmol/mg protein) of fetuses and newborns were significantly greater than those of adults. Western immunoblotting assay also revealed that the density of L-type Ca2+ channel protein in the cerebral arteries and CCA was about twofold greater in the fetus than the adult. Finally, compared with the adult, fetal cerebral arteries demonstrated a significantly greater maximum tension and [Ca2+]i in response to stimulation with the L-type Ca2+ channel agonist Bay K 8644. In addition, Bay K 8644-stimulated fetal vessels demonstrated a maximal tension and [Ca2+]i similar to that observed in response to stimulation with 10(-4) NE. These results support the idea that fetal cerebrovascular smooth muscle relies more on extracellular Ca2+ and L-type Ca2+ channels for contraction than does the adult and that this increased reliance is mediated, in part, by greater L-type Ca2+ channel density. This may have important implications in the regulation of cerebral blood flow in the developing organism.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed2002

Pre- and postjunctional alpha(2)-adrenergic receptors in fetal and adult ovine cerebral arteries.

In ovine cerebral arteries, adrenergic-mediated vasoconstrictor responses differ significantly with developmental age. We tested the hypothesis that, in part, these differences are a consequence of altered alpha(2)-adrenergic receptor (alpha(2)-AR) density and/or affinity. In fetal (approximately 140 days) and adult sheep, we measured alpha(2)-AR density and affinity with the antagonist [(3)H]idazoxan in main branch cerebral arteries and other vessels. We also quantified contractile responses in middle cerebral artery (MCA) to norepinephrine (NE) or phenylephrine in the presence of the alpha(2)-AR antagonists yohimbine and idazoxan and contractile responses to the alpha(2)-AR agonists clonidine and UK-14304. In fetal and adult cerebral artery homogenates, alpha(2)-AR density was 201 +/- 18 and 52 +/- 6 fmol/mg protein, respectively (P < 0.01); however, antagonist affinity values did not differ. In fetal, but not adult, MCA, 10(-7) M yohimbine significantly decreased the pD(2) for NE-induced tension in the presence of 3 x 10(-5) M cocaine, 10(-5) M deoxycorticosterone, and 10(-6) M tetrodotoxin. In fetal, but not adult, MCA, UK-14304 induced a significant decrease in pD(2) for the phenylephrine dose-response relation. In addition, stimulation-evoked fractional NE release was significantly greater in fetal than in adult cerebral arteries. In the presence of 10(-6) M idazoxan to block alpha(2)-AR-mediated inhibition of prejunctional NE release, the fractional NE release was significantly increased in both age groups. We conclude that in fetal and adult ovine cerebral arteries, alpha(2)-AR appear to be chiefly prejunctional. Nonetheless, the fetal cerebral arteries appear to have a significant component of postjunctional alpha(2)-AR.

Adrenergic alpha-2 Receptor Agonists↗
PubMed2002

[The relationship between expression of lung resistance-related protein gene or multidrug resistance-associated protein gene and prognosis in newly diagnosed acute leukemia].

OBJECTIVE: To evaluate the relationship between the expression of lung resistance-related protein (lrp) gene or multidrug resistance-associated protein (mrp) gene and prognosis in untreated acute leukemia (AL) patients. METHODS: Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to examine the expression of lrp and mrp gene in 58 newly diagnosed AL patients. RESULTS: The positive rate of lrp and mrp gene expression in newly diagnosed acute lymphocytic leukemia (ALL) group was 15.0% and 40.0% and it was 15.8% and 42.1% in newly diagnosed acute nonlymphocytic leukemia (ANLL) group. In both the ALL and ANLL groups, the difference of the first complete remission rate in lrp negative and in lrp positive patients was not significant (P > 0.05), the same results were found with mrp gene. The difference of the first complete remission rate between lrp(+)/mrp(+) and lrp(-)/mrp(-) patients was significant (P < 0.05). There was no relationship between lrp and mrp gene. CONCLUSION: Neither lrp nor mrp gene as a single indicator to forecast original multidrug resistance is sensitive, but lrp combined with mrp as one indicator will be sensitive.

ATP-Binding Cassette Transporters↗
PubMed2002

[The applications of the dermal vault technique in mammaplasty].

OBJECTIVE: To search for the applications of the dermal vault in mammaplasty. METHODS: The dermal vault was planned as large as possible according to the degree of the macromastia and mammaptosis. The residual gland was sculptured and fixed with the dermal vault in order to reconstruct the protrude, pliable and living breasts. RESULTS: The 27 cases (53 breast) were performed with this technique. The result is satisfactory and there are no complications. CONCLUSION: It is a good method to use the dermal vault as a sculpturing and fixing material in mammaplasty. The breasts formed are projecting, pliable and moveable. The scar is not apparent and the result is persistent.

Adult↗
PubMed2002

[Change of adhesion molecule expression on CD34(+) cells from bone marrow and peripheral blood during mobilization with combination of chemotherapy and G-CSF].

To explore the dynamic change of CD34(+) cell expressing adhesion molecules in bone marrow and peripheral blood during mobilization with combination of chemotherapy and G-CSF and its clinical significance, mononuclear cells of bone marrow and peripheral blood from malignant hematopathy cases before and after mobilization with G-CSF were labeled by CD45-CY-Chrome, PE conjugated anti-CD34, and FITC conjugated anti-CD44, anti-CD49d, anti-CD62L and anti-CXCR4. For three-color fluorescence analysis by flow cytometry was performed on a FACScalibur. Also the relationship between the number of subpopulations in different expressions of adhesion molecules infused and the time of recovery in different blood cells after transplantation was evaluated. Results showed that a significantly lower expression of CD44(+) and CD49d(+) on CD34(+) cells in bone marrow after mobilization compared to that before mobilization, whereas great higher expression of CD44(+), CD49d(+), anti-CD62L(+) and lower of anti-CXCR4(+) in peripheral blood were observed after mobilization. No significant relations were found between expression of different adhesion molecules on CD34(+) cells infused and the time of reconstitution in blood cells after transplantation. It was concluded that this mobilizing regimen could downregulate the expressions of CD44, CD49d, CD62L, and anti-CXCR4 on CD34(+) cells in bone marrow, it may related to mobilization of CD34(+) cells from marrow to blood, and homing of blood CD34(+) cells into marrow.

Adolescent↗
PubMed2002

[A linkage study of cytotoxic T lymphocyte-associated antigen 4 gene and Graves' disease in northern Chinese Han ethnic].

OBJECTIVE: To determine if the cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) gene, which is located on chromosome 2q31-q33, is the major susceptibility gene for Graves' disease (GD) of northern Chinese Han nationality. METHODS: Five highly polymorphic microsatellite markers spanning the entire region of chromosome 2q31-q33 were employed to screen 54 families with multiple incidences of GD (322 individuals) of northern Chinese Han nationality. Tow-point and multi-point Lod scores were calculated under different levels of penetrance, assuming both dominant and recessive models. Multipoint nonparametric linkage (NPL) scores were also calculated. RESULTS: Two-point Lod scores (theta = 0) and multipoint Lod scores of less than -2 were observed for all the markers tested, at all levels of penetrance, in both the dominant and recessive models of inheritance. P values of greater than 0.05 were observed for all the multipoint NPL scores obtained. CONCLUSION: We obtained evidence against the linkage of GD with chromosome 2q31-q33, thus we are of the opinion that CTLA-4 gene is not the major susceptibility locus for Graves' disease of northern Chinese Han nationality.

Abatacept↗
PubMed2002

[Repair of large facial defect with an expanded clavicular-pectoral skin flap].

OBJECTIVE: To search for an ideal method to repair large facial defects. METHODS: One or two soft tissue expanders were implanted at the clavicular-pectoral region. After fully expansion, a clavicular-pectoral skin flap was designed and created with similar color, texture, and size to the facial defect. The flap would pass over the neck and transfer to the face to repair a large defect. RESULTS: 10 cases were treated with this method. All have been followed up for 12-18 months with satisfactory results. CONCLUSION: The large facial defects could be repaired by the expanded clavicular-pectoral skin flap without damaging the natural neck contour and donor site abnormality was avoided. The patients get an aesthetic look and good function.

Adolescent↗
PubMed2002

[Application of beta-cyclodextrin inclusion technique in new dosage form of angelica sinensis essential oil].

OBJECTIVE: To make a solid form of Angelica Sinensis essential oil by preparing its inclusion compound with beta-cyclodextrin and evaluate the inclusion rate, dissolution rate and liberating rate of this complex. METHOD: GC-MS, X-ray diffraction and thin-layer chromatography were applied to characterize the essential oil and the inclusion compound. RESULT: The inclusion compound was shown to form a new phase by X-ray diffraction analysis. GC-MS and TLC check-up corroborated the composition of the free oil and the inclusion oil remaining the same. CONCLUSION: The results showed Angelica Sinensis essential oil was more stable with beta-cyclodextrin inclusion. The preparation of this inclusion compound has advantages in limited amount, long time effect, easily preserved and convenient administration as a new dosage form.

Angelica sinensis↗
PubMed2001

[The Application of RACE Technique to Clone the Full-Length cDNA of A Novel Leukemia Associated Gene LRP16]

LRP16 is a novel gene which was found in our laboratory by using methylation-sensitive restriction landmark genomic scanning (RLGS) technique. In order to clone the full-length cDNA of this leukemia relapse associated gene, the method of rapid amplification of cDNA end (RACE) was employed. By optimizing some procedures of RACE method, the 5'- and 3'-untranslated region of LRP16 cDNA was successfully sequenced. Then, the full length of LRP16 cDNA and open reading frame (ORF) was constructed and was registered in GenBank. The above-mentioned procedure demonstrated RACE technique is a rapid and sensitive method for cloning unknown gene. Especially, it is very useful to cloning the 5'- and 3'-untranslated region of a novel gene.

Journal Article↗
PubMedDate not supplied

Total synthesis and cytotoxicity evaluation of syrinenin-4-O-farnesylether and its analogues.

First synthesis of natural product, syrinenin-4-O-farnesylether (1), was carried out via two different paths. Four of its derivatives (9-12) were also prepared. Cytotoxicity screening of the selected compounds were performed on six tumour cell lines. Compound 12 exhibited prominent IC50 values of 1.9 microM and 0.8 microM on CNE and PC-3 cells, respectively.

Alkenes↗