Biomedical subjects

Ying Zhu

Publications and source records attributed to Ying Zhu.

106 records · Page 6Linked to original sources

PubMed2003

[Study of midazolam for premedication in oral and maxillofacial surgery].

OBJECTIVE: To study the effects of midazolam for premedication in oral-maxillofacial surgery. METHODS: 60 patients were selected and divided into 3 groups equally with 20 cases in each group. Different drugs were used for premedication. Group received midazolam 0.06 mg/kg, group received diazepam 0.12 mg/kg, group received luminal 3 mg/kg, Intramuscular injections of drugs were finished before 30 minutes of anesthesia. The sedative and anxiolytic effects, the changes of circulation and respiration and the side effects were evaluated. RESULTS: In group, BIS (bispectral analysis of electroencephalogram) decreased obviously and Ramsay score increased significantly 5 minutes after drug administration, AVAT(Anxiety visual analog test) and SAI(State anxiety inventory) decreased obviously 30 minutes after administration drug (P < 0.05). But no significant changes in the other groups (P > 0.05). There were no remarkable changes of circulation and respiration in the three groups. No severe side effects were observed after premedication. CONCLUSION: The premedication of using midazolam has good sedative and anxiolytic effects and few side effects.

Adolescent↗

PubMed2003

[A comparison of the mRNA expression of VEGF and its receptor FLK-1 in rabbit iris pigment epithelium cells and retinal pigment epithelial cells].

OBJECTIVE: To investigate mRNA expression of vascular endothelial growth factor (VEGF) and its receptor FLK-l in iris pigment epithelium (IPE) cells and retinal pigment epithelium (RPE) cells, and the feasibility of transplantation of autologous IPE cells to substitute RPE in the treatment of age-related macular degeneration (AKMD) and diseases of RPE dysfunction. METHODS: IPE and RPE cells were isolated from pigmented rabbits. The expression of mRNA for VEGF and FLK-l were detected by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Rabbit IPE and RPE cells express VEGF mRNA and FLK-l; the express of VEGF and FLK-1 mRNA in IPE cells was relatively low compared with the expression in RPE cells. The amount of VEGF mRNA in IPE cells was 44.62% of RPE cells, and amount of FLK-l mRNA was 52.36% of RPE cells- The results of the differences of expression of VEGF and FLK-l mRNA between IPE and RPE cells was statistically significant (t-test, P < 0.001). CONCLUSIONS: VEGF and FLK-l mRNA in IPE cells express is relatively low compared with the expression in RPE cells, and the results suggest that IPE cells could be more beneficial than RPE cells in the transplantation into the subretinal space.

Animals↗

PubMed2002

Expression of a novel member of sorting nexin gene family, SNX-L, in human liver development.

The sorting nexin (SNX) protein family is implicated in the regulation of receptor degradation and membrane traffic in the cell. With the aim of identifying novel genes involved in receptor degradation and recycling, we have cloned a new member of the sorting nexin gene family, human sorting nexin L, SNX-L (or SNX21). This gene includes 4 exons and 3 introns, and is located on chromosome 20q12-13.1 region, encompassing 8 kb. The full-length cDNA of SNX-L is 1,811 bp, with an open reading frame of 1,092 bp. The protein consists of 364 amino acids and encodes a 40 kDa protein. The SNX-L protein has a common PX domain shared by all SNX family members. The similarity of SNX-L PX domain to the PX consensus sequence is over 40%. PX domains have been shown to associate with specific phospholipids and membrane compartments. Expression analysis of SNX-L mRNA indicates that SNX-L is distinctly and highly expressed in fetus liver, but only weakly expressed in brain, muscle (skeleton muscle, smooth muscle, and cardiac muscle), kidney, and adrenal gland. Strong liver expression of SNX-L is maintained from 12 to 25 weeks during human fetus development, suggesting that SNX-L may be a regulatory gene involved in receptor protein degradation during embryonic liver development.

Amino Acid Sequence↗

PubMed2002

Up-regulation of p300 binding and p50 acetylation in tumor necrosis factor-alpha-induced cyclooxygenase-2 promoter activation.

It is well established that p300 plays an important role in mediating gene expressions. However, it is less clear how its binding is influenced by physiological stimuli and how its altered binding affects transactivator acetylation and binding. In this study, we determined p300 binding to a core cyclooxygenase-2 (COX-2) promoter region by chromatin immunoprecipitation and streptavidin-agarose pull-down assays in basal and tumor necrosis factor-alpha (TNFalpha)-treated human foreskin fibroblasts. We found basal binding of p300, p50/p65 NF-kappaB, cyclic AMP regulatory element-binding protein-2, CCAAT/enhancer-binding protein beta, and c-Jun. p50/p65 and p300 binding was selectively increased by TNFalpha. Immunoprecipitation confirmed direct interaction of p300 with NF-kappaB and the other involved transactivators. p50 acetylation was detected in resting cells and was increased by TNFalpha or lipopolysaccharide. Overexpression of p300 augmented p50 acetylation, which was attenuated by deletion of its histone acetyltransferase domain. Enhanced p50 acetylation correlated with increased p50 binding to COX-2 promoter and transcriptional activation. Co-transfection of E1A with p300 abrogated p50 acetylation and p50 binding. These findings suggest that up-regulation of p300 binding and its acetylation of NF-kappaB occupies a central position in COX-2 promoter activation.

Acetylation↗

PubMed2002

Salicylate suppresses macrophage nitric-oxide synthase-2 and cyclo-oxygenase-2 expression by inhibiting CCAAT/enhancer-binding protein-beta binding via a common signaling pathway.

We determined whether salicylate at pharmacological concentrations inhibits nitric-oxide synthase-2 (NOS-2) and cyclo-oxygenase-2 (COX-2) expressions in RAW 264.7 stimulated with lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma). Cells were treated with sodium salicylate (10(-7)-10(-4) m) or vehicle for 30 min followed by LPS+IFN-gamma for up to 24 h. Salicylate suppressed NOS-2 and COX-2 protein levels and promoter activities stimulated by LPS+IFN-gamma for 4 h in a concentration-dependent manner but had no effect on NOS-2 expression stimulated by the combined agonists for 24 h. Results from promoter analysis indicate that the binding of CCAAT/enhancer-binding protein beta (C/EBPbeta) to its cognate site at -150/-142 on the NOS-2 promoter region was essential for NOS-2 expression at 4 h but not at 24 h. Salicylate reduced C/EBPbeta binding at 4 h and did not alter its binding at 24 h. NOS-2 and COX-2 protein levels and C/EBPbeta binding stimulated by LPS+IFN-gamma for 4 h were inhibited by a similar battery of signaling inhibitors, suggesting a common pathway for NOS-2 and COX-2 expression. Kinetic analysis indicates that NOS-2, similar to COX-2 expression, at 4 h was largely due to the action of LPS, which induced C/EBPbeta binding, whereas its expression at a longer time point was contributed by IFN-gamma. Our findings implicate two distinct pathways for NOS-2 expression induced by LPS+IFN-gamma. Salicylate at pharmacological concentrations is capable of suppressing the early phase of NOS-2 and COX-2 expression by blocking C/EBPbeta binding.

Animals↗

PubMed2002

Obligatory role of cyclic adenosine monophosphate response element in cyclooxygenase-2 promoter induction and feedback regulation by inflammatory mediators.

BACKGROUND: Cyclooxygenase-2 (COX-2) plays a key role in human inflammatory disorders such as vascular inflammation. COX-2 promoter activity is induced by proinflammatory mediators, but the role of cyclic adenosine monophosphate response element (CRE) in promoter stimulation remains unclear. METHODS AND RESULTS: Transient transfection of a 0.9-kb COX-2 promoter fragment bearing CRE mutation abrogated COX-2 promoter activity induced by proinflammatory mediators in human endothelial cells and fibroblasts. Dual mutations of CRE and an upstream CCAAT/enhancer binding protein (C/EBP) site did not have an additional effect. Binding of CREB-2, ATF-2, USF-2, and c-Jun transactivators to a wild-type and CRE-mutated oligonucleotide was analyzed by a novel DNA-binding assay. CREB-2 and ATF-2 in nuclear extracts of unstimulated endothelial cells bound to CRE, whereas USF-2 and c-Jun or c-Fos bound to non-CRE sites. CREB-2 and c-Fos binding was increased by phorbol 12-myristate 13-acetate but not tumor necrosis factor-alpha. The binding assay and chromatin immunoprecipitation revealed binding of P300 coactivator to the COX-2 promoter region. CONCLUSIONS: CRE plays an obligatory role in COX-2 promoter activation by diverse stimuli. CREB-2 and ATF-2 bound to CRE serve as an anchor for P300 interaction with upstream transactivators and downstream transcription machinery.

Activating Transcription Factor 4↗

PubMed2002

Purification and characterization of a cyclooxygenase-2 and angiogenesis suppressing factor produced by human fibroblasts.

Cyclooxygenase-2 (COX-2) is an inducible enzyme that plays an important role in several pathophysiological processes, including inflammation, angiogenesis, and tumorigenesis. We have recently observed that COX-2 induction is restrained in proliferating fibroblasts. The mechanism by which this occurs is unclear. Here, we report the detection and isolation from the conditioned medium of proliferating fibroblasts a factor that suppressed COX-2 expression. This factor, which was named cytoguardin, suppressed COX-2 protein levels induced by phorbol 12-myristate 13-acetate, interleukin-1beta, tumor necrosis factor alpha, and lipopolysaccharide (LPS) in fibroblasts and LPS-induced COX-2 protein levels and promoter activities in human endothelial cells and murine RAW 264.7 cells in a comparable concentration-dependent manner. It inhibited COX-2 expression induced by angiogenic factors and endothelial tube formation induced by angiogenic factors and colon cancer cell medium. These findings provide evidence for the control of COX-2 transcription by an endogenous cellular factor.

Angiogenesis Inhibitors↗

PubMed2002

Alterations in the suppressor gene PPP2R1B in parathyroid hyperplasias and adenomas.

Deletion of chromosome 11q23 is a common alteration in parathyroid adenomas and hyperplasias. A new potential suppressor gene PPP2R1B encoding the beta isoform of the A subunit of the serine/threorine protein phosphatase 2A was recently identified and localized to chromosome 11q23. We performed polymerase chain reaction-based single-strand conformation polymorphism and direct sequencing on six parathyroid hyperplasias and 12 adenomas to evaluate the role of PPP2R1B in the pathogenesis of parathyroid lesions. A previously identified germline G-A transition (GGC-GAC) in codon 90, changing glycine (Gly) to aspartic acid (Asp), was detected in one adenoma. Both the common Gly allele and the variant Asp allele were detected by direct sequencing in the patient's somatic cells. We conclude mutations of PPP2R1B are not frequent in parathyroid lesions, and that other genes located at 11q23 may be more closely associated with pathogenesis of parathyroid hyperplasia and adenoma.

Adenoma↗

PubMed2002

Refolding and reactivation of calf intestinal alkaline phosphatase with excess magnesium ions.

It is well known that Mg(2+) is an essential component in many biological processes. This research investigated the courses of both the reactivation and the refolding in the absence and presence of Mg(2+) ions. Calf intestinal alkaline phosphatase (CIP) was extensively denatured in 3 M guanidine hydrochloride (GdnHCl) solution for 2 h. Under suitable renaturation conditions, about 60-70% of the activity was recovered in the absence and presence of different magnesium ion concentrations. The refolding processes followed two-phase courses, whereas the reactivation processes were monophasic after dilution in proper solutions with or without Mg(2+). The magnesium ions affected both the reactivation and the refolding courses of unfolded CIP. A comparison of rate constants for the refolding of unfolded CIP with those for recovery of enzyme activity at different Mg(2+) concentrations showed that they were not synchronized. The activity recovery was speeded up due to the presence of Mg(2+) ions; while the refolding course of unfolded CIP was somewhat inhibited by the excess Mg(2+).

Alkaline Phosphatase↗

PubMed2002

Investigatory and analytical approaches to differential gene expression profiling in mantle cell lymphoma.

Mantle cell lymphoma (MCL) is a non-Hodgkin's lymphoma of B-cell lineage. The blastoid variant of MCL, characterized by high mitotic rate, is clinically more aggressive than common MCL. We used the cDNA array technology to examine the gene expression profiles of both blastoid variant and common MCL. The data was analysed by regression analysis, principal component analysis and the naive Bayes' classifier. Eight genes were identified as differentially deregulated between the two groups. Oncogenes CMYC, BCL2 and PIM1 were upregulated more frequently in the blastoid variant than in common MCL. This implied that the gp130-mediated signal transducer and activator of transcription 3 (STAT3) signalling pathway was involved in the blastoid variant transformation of MCL. Other differentially deregulated genes were TOP1, CD23, CD45, CD70 and NFATC. By using the eight differentially deregulated genes, we created a classifier to distinguish the blastoid variant from common MCL with high accuracy. We also identified 18 genes that were deregulated in both groups. Among them, BCL1, CALLA/CD10 and GRN were suggested to be oncogenes. The products of RGS1, RGS2, ANX2 and CD44H were suggested to promote tumour metastasis. CD66D was suggested to be a tumour suppressor gene.

Aged↗

PubMed2002

[Effect of cyclosporin A on the growth of human first trimester cytotrophoblasts in vitro].

OBJECTIVE: To investigate effect of cyclosporin A (CsA) on the growth of first trimester human cytotrophoblast in vitro. METHODS: To isolate and purificate first trimester human cytotrophoblasts by way of percoll density gradient centrifugation; to evaluate the effect of CsA on in vitro proliferation of cytotrophoblasts using (3)H-thymidine incorporation assay; to analyze of cell cycle of cytotrophoblasts with flow cytometric assay; and to survey morphology of the cells by scanning electro-microscope respectively. RESULTS: CsA could increase in vitro proliferation of first trimester human cytotrophoblasts when concentration of CsA ranged from 1 x 10(-4) micromol/L to 1 micromol/L, but decrease in vitro proliferation of the cells if the concentration reached to 10 micromol/L. G(2)-M phase increased from (2.8 +/- 0.5)% to (6.7 +/- 1.3)% when the cytotrophoblasts were incubated with culture medium containing 1 micromol/L CsA for 24 hours, while S phase increased from (14 +/- 5)% to (28 +/- 8)% and apoptosis decreased from (8.7 +/- 2.2)% to (3.6 +/- 1.0)% when the culture in the same incubating condition lasted for 48 hours. Pseudopodia of the trophoblasts increased in number and length when they were incubated in culture medium containing 1 micromol/L of CsA for 48 hours, but decreased if the concentration reached to 10 micromol/L with the same incubating duration. CONCLUSION: CsA is able to promote growth of first trimester human cytotrophoblasts and change their morphology, which appears to increase in invasive ability.

Apoptosis↗

PubMed2002

[Missed diagnostic cholesteattomaous otitismedia].

OBJECTIVE: To explore the missed diagnostic cholesteattomaous otitismedia lacked of clinical symptoms in order to minimize the mistake in clinical diagnose. METHODS: A retrospective study of 31 cases with the missed diagnostic cholesteattomaous otitismedia, confirmed by surgery and pathology, was conducted. RESULTS: Twenty-one cases (67.7%) had not obvious otorrhea. There were only slight finding such as attic retraction, apophysis, small granulation tissue, ear wax covered or tiny, even non, perforation in the pars flaccida or the superior and posterior pars tensa of the ear-drum. In general, the hearing loss is slight or medium conductive deafness. The type B curve was showed in tympanogram. The diagnosis rate of X-ray was only 41.9%, and 80.7% for the computed tomography. The middle ear structures aggressed by cholesteames was epitympanum, ossicular chain, tympanic antrum, mastoid process and mesotympanum. The complications occurred in 11 cases (35.5%) were the expose of facial nerve or and the meninges, or, and the labyrinth fistula. CONCLUSION: The cases with the cholesteatoma lack obvious clinic symptoms would result in the missed diagnosis because of slow and long term during cholesteatoma development. Sometimes misdiagnosed or missed diagnosis happened to in such cases of cholesteatoma with little clinical manifestation, and it is so dangerous for the patients in such case. Therefore, otolaryngologist must pay more attention to the missed diagnostic cholesteattomaous otitismedia.

Adolescent↗

PubMed2001

Dynamic regulation of cyclooxygenase-2 promoter activity by isoforms of CCAAT/enhancer-binding proteins.

To elucidate the mechanism by which isoforms of CCAAT/enhancer-binding proteins regulate cyclooxygenase-2 expression, we determined by a novel technique binding of six isoforms of this transactivator to two sequence-specific CCAAT/enhancer-binding protein (-132/-125) and cyclic AMP (-59/-53) regulatory elements in human foreskin fibroblasts treated with phorbol 12-myristate 13-acetate for 4 h. The delta isoform bound to these two elements at basal state, which was displaced by full-length as well as two truncated beta isoforms, a 41-kDa liver-enriched activating protein and a 16-kDa liver-enriched inhibitory protein, after phorbol ester stimulation. Kinetic analysis shows time-dependent changes in beta and delta binding that were concordant with time-dependent increase in cyclooxygenase-2 induction. Overexpression of the 16-kDa beta isoform blocked the promoter activity and protein level induced by phorbol ester. Paradoxically, it increased binding of beta isoforms to the sequence-specific promoter DNA but suppressed cyclooxygenase-2 promoter activation by p300 cotransfection. These findings provide new insight into the regulation of cyclooxygenase-2 promoter by an interplay between two opposite beta isoforms and p300 co-activator.

Acetyltransferases↗

PubMed2001

Spontaneous Vesicle Formation in Aqueous Mixtures of Cationic Surfactants and Partially Hydrolyzed Polyacrylamide.

Spontaneous vesicle formation was observed in aqueous mixtures of partially hydrolyzed polyacrylamide and single-tailed cationic surfactants. The influences of pH, addition of long-chain alcohols, variation of hydrocarbon chain length, and head group size of the cationic surfactants were investigated systematically. It was found that 30-50% hydrolyzed degree of polyacrylamide and cationic surfactants with 10 or 12 methylene groups are suitable for vesicle formation in the mixed aqueous systems at pH 9.2. Addition of long-chain alcohols was found to be helpful for vesicle formation in some cases. The vesicle stability was also investigated at various temperatures and amounts of ethanol addition. Copyright 2001 Academic Press.

Journal Article↗

PubMedDate not supplied

Adaptation of Clostridium tyrobutyricum for enhanced tolerance to butyric acid in a fibrous-bed bioreactor.

By immobilization in a fibrous-bed bioreactor (FBB), we succeeded in adapting and selecting an acid-tolerant strain of Clostridium tyrobutyricum that can produce high concentrations of butyrate from glucose and xylose. This mutant grew well under high butyrate concentrations (>30 g/L) and had better fermentative ability as compared to the wild-type strain used to seed the bioreactor. Kinetic analysis of butyrate inhibition on cell growth, acid-forming enzymes, and ATPase activity showed that the adapted cells from the FBB are physiologically different from the original wild type. Compared to the wild type, the adapted culture's maximum specific growth rate increased by 2.3-fold and its growth tolerance to butyrate inhibition increased by 29-fold. The key enzymes in the butyrate-forming pathway, phosphotransbutyrylase (PTB) and butyrate kinase (BK), were also more active in the mutant, with 175% higher PTB and 146% higher BK activities. Also, the mutant's ATPase was less sensitive to inhibition by butyric acid, as indicated by a 4-fold increase in the inhibition rate constant, and was more resistant to the enzyme inhibitor N,N'-dicyclohexylcarbodiimide (DCCD). The lower ATPase sensitivity to butyrate inhibition might have contributed to the increased growth tolerance to butyrate inhibition, which also might be attributed to the higher percentage of saturated fatty acids in the membrane phospholipids (74% in the mutant vs 69% in the wild type). This study shows that cell immobilization in the FBB provides an effective means for in-process adaptation and selection of mutant with higher tolerance to inhibitory fermentation product.

Adaptation, Physiological↗

PubMedDate not supplied

Construction and characterization of ack deleted mutant of Clostridium tyrobutyricum for enhanced butyric acid and hydrogen production.

Clostridium tyrobutyricum produces butyrate, acetate, H(2), and CO(2) as its main fermentation products from glucose and xylose. To improve butyric acid and hydrogen production, integrational mutagenesis was used to create a metabolically engineered mutant with inactivated ack gene, encoding acetate kinase (AK) associated with the acetate formation pathway. A non-replicative plasmid containing the acetate kinase gene (ack) fragment was constructed and introduced into C. tyrobutyricum by electroporation. Integration of the plasmid into the homologous region on the chromosome should inactivate the target ack gene and produce ack-deleted mutant, PAK-Em. Enzyme activity assays showed that the AK activity in PAK-Em decreased by approximately 50%; meanwhile, phosphotransacetylase (PTA) and hydrogenase activities each increased by approximately 40%. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) results showed that the expression of protein with approximately 32 kDa molecular mass was reduced significantly in the mutant. Compared to the wild type, the mutant grew more slowly at pH 6.0 and 37 degrees C, with a lower specific growth rate of 0.14 h(-1) (vs 0.21 h(-1) for the wild type), likely due to the partially impaired PTA-AK pathway. However, the mutant produced 23.5% more butyrate (0.42 vs 0.34 g/g glucose) at a higher final concentration of 41.7 g/L (vs 19.98 g/L) as a result of its higher butyrate tolerance as indicated in the growth kinetics study using various intial concentrations of butyrate in the media. The mutant also produced 50% more hydrogen (0.024 g/g) from glucose than the wild type. Immobilized-cell fermentation of PAK-Em in a fibrous-bed bioreactor (FBB) further increased the final butyric acid concentration (50.1 g/L) and the butyrate yield (0.45 g/g glucose). Furthermore, in the FBB fermentation at pH 5.0 with xylose as the substrate, only butyric acid was produced by the mutant, whereas the wild type produced large amounts of acetate (0.43 g/g xylose) and lactate (0.61 g/g xylose) and little butyrate (0.05 g/g xylose), indicating a dramatic metabolic pathway shift caused by the ack deletion in the mutant.

Acetate Kinase↗