PubMed Health⌕ Search

Biomedical subjects

Yin Liu

Publications and source records attributed to Yin Liu.

At least 37 records · Page 2Linked to original sources
PubMed2006

Adapalene gel 0.3% for the treatment of acne vulgaris: a multicenter, randomized, double-blind, controlled, phase III trial.

BACKGROUND: A new 0.3% gel formulation of adapalene has been developed. OBJECTIVE: We sought to provide evidence of the superiority of adapalene gel 0.3% over adapalene gel 0.1% and gel vehicle in the treatment of acne. METHODS: A total of 653 patients were randomized to receive adapalene gel 0.3%, adapalene gel 0.1%, or vehicle once daily for 12 weeks (2:2:1 randomization). Analysis for efficacy was conducted on correlated repeated measurements at weeks 8 and 12 using Generalized Estimating Equation methodology. RESULTS: Adapalene gel 0.3% was significantly superior to adapalene gel 0.1% and vehicle in success rate, total lesion count, and inflammatory lesion count. A consistent, dose-dependent effect was demonstrated for all efficacy measures. Signs and symptoms were mostly mild to moderate and transient in nature. LIMITATIONS: Adjunctive topical or oral agents and their impact on acne were not studied in this trial. CONCLUSIONS: Adapalene gel 0.3% was effective and well tolerated in the treatment of acne.

Acne Vulgaris↗
PubMed2006

Inhibition of the alpha-mannosidase Man2c1 gene expression enhances adhesion of Jurkat cells.

Protein N-glycosylation plays very important roles in immunity and alpha-mannosidase is one of the key enzymes in N-glycosylation. This paper reports that inhibition of alpha-mannosidase Man2c1 gene expression enhances adhesion of Jurkat T cells. In comparison to the controls with normal expression of the enzyme, Jurkat cells with the inhibition of Man2c1 gene expression (AS cell) formed larger aggregates in culture, indicating an enhancement of adhesion between the cells. mRNA differential display analysis discovered up-regulation of several adhesion molecule genes in the AS cell. Because of the pivotal role played by CD54-LFA-1 interaction in immune cell interaction, this study focused on the contribution of enhanced expression of CD54 and LFA-1 to the enhanced adhesion of AS Jurkat cells. These facts, including increased binding of AS cells to ICAM-1-Fc, Mg(2+) activation of the binding of AS cells to ICAM-1-Fc and enhanced aggregation of AS cells, together with the inhibiting effect of a blocking CD11a mAb on the binding to ICAM-1-Fc and aggregation of the cells demonstrate an important contribution of enhanced CD54-LFA-1 interaction to increased adhesion between AS cells. The enhanced CD54-LFA-1 interaction also resulted in increased adhesion between AS Jurkat T cells and Raji B cells. In addition, AS cells showed cytoskeletal rearrangement. The data imply a biological significance of MAN2C1 in T-cell functioning.

Cell Adhesion↗
PubMed2006

CpG-modified plasmid DNA encoding flagellin improves immunogenicity and provides protection against Burkholderia pseudomallei infection in BALB/c mice.

The plasmid DNA encoding the fliC gene of Burkholderia pseudomallei combined with CpG oligodeoxynucleotide (ODN) was injected intramuscularly into BALB/c mice, resulting in the increased production of certain humoral antibodies and flagellin-specific spleen cell clonal expansion. CpG ODN, as an immunoadjuvant, was added to the plasmid containing the fliC gene in order to obtain ongoing expression in muscle for a long period. Functional expression of flagellin from the constructed CpG-modified plasmid in transfected peritoneal exudate cells of BALB/c mice was shown by reverse transcription-PCR and Western blotting. Furthermore, BALB/c mice immunized with the modified plasmid had relatively higher resistance to B. pseudomallei infection in vivo than did mice immunized with unmodified plasmid DNA. The time course of restricted bacterial growth in spleen and liver and changes in the cytokine profiles of immunized mice suggested that the stimulated phagocytic cells would be able to kill the bacteria eventually, possibly as a consequence of the induction of Th-1-type immune polarization in vivo. Th-1-type immune polarization was detected in response to flagellin induction in mice immunized with CpG-modified plasmid DNA by the appearance of increased levels of immunoglobulin G2a antibodies and gamma interferon-secreting cells specific to flagellin. The exogenous CpG motifs added to the fliC gene would contribute to an adjuvant-like response that enhances the flagellin-specific immunogenicity and provides protection against B. pseudomallei infection. This CpG-modified plasmid DNA vaccination is an important potential strategy that should be developed to protect against melioidosis.

Adjuvants, Immunologic↗
PubMed2006

Role of the mitochondrial signaling pathway in murine coronavirus-induced oligodendrocyte apoptosis.

A previous study demonstrated that infection of rat oligodendrocytes by mouse hepatitis virus (MHV) resulted in apoptosis, which is caspase dependent (Y. Liu, Y. Cai, and X. Zhang, J. Virol. 77:11952-11963, 2003). Here we determined the involvement of the mitochondrial pathway in MHV-induced oligodendrocyte apoptosis. We found that caspase-9 activity was 12-fold higher in virus-infected cells than in mock-infected cells at 24 h postinfection (p.i.). Pretreatment of cells with a caspase-9 inhibitor completely blocked caspase-9 activation and partially inhibited the apoptosis mediated by MHV infection. Analyses of cytochrome c release further revealed an activation of the mitochondrial apoptotic pathway. Stable overexpression of the two antiapoptotic proteins Bcl-2 and Bcl-xL significantly, though only partially, blocked apoptosis, suggesting that activation of the mitochondrial pathway is partially responsible for the apoptosis. To identify upstream signals, we determined caspase-8 activity, cleavage of Bid, and expression of Bax and Bad by Western blotting. We found a drastic increase in caspase-8 activity and cleavage of Bid at 24 h p.i. in virus-infected cells, suggesting that Bid may serve as a messenger to relay the signals from caspase-8 to mitochondria. However, treatment with a caspase-8 inhibitor only slightly blocked cytochrome c release from the mitochondria. Furthermore, we found that Bax but not Bad was significantly increased at 12 h p.i. in cells infected with both live and UV-inactivated viruses and that Bax activation was partially blocked by treatment with the caspase-8 inhibitor. These results thus establish the involvement of the mitochondrial pathway in MHV-induced oligodendrocyte apoptosis.

Animals↗
PubMed2006

PI3K-Akt signaling is involved in the regulation of p21(WAF/CIP) expression and androgen-independent growth in prostate cancer cells.

The purpose of this study is to investigate the role of PI3K-Akt signaling in prostate cancer cell growth and androgen receptor (AR)-mediated gene expression. Androgen-dependent LNCaP cells and their androgen-independent counterpart, LNCaP-AI cells, were used. We found that PI3K-Akt signaling is elevated in LNCaP-AI cells compared to that in LNCaP cells and is involved in androgen-independent growth. More importantly, PI3K-Akt signaling enhances AR activity and is involved in the induction of AR target genes, such as p21(WAF/CIP), a gene with anti-apoptosis activity and associated with androgen-independent growth in human prostate cancer. A receptor tyrosine kinase inhibitor also inhibits the PI3K-Akt signaling and compromises AR activity and cell growth. These findings suggest that the PI3K-Akt cell growth survival pathway and its downstream-regulated gene, p21(WAF/CIP), are targets for developing novel therapies against prostate cancer, especially those androgen-independent diseases.

Androgens↗
PubMed2006

[Spectroscopy research on cholesterol in hypercholesterolemia serum].

The cholesterol with different concentration in hypercholesterolemia serum was studied by the method of spectroscopy technology. The absorption and fluorescence spectra of normal human serum and hypercholesterolemia serum were obtained respectively; the spectral characteristic of each sample and the difference between two kinds of samples were discussed too. The results indicate that the absorption and fluorescence spectra of hypercholesterolemia serum are different from those of normal human serum. The absorptivity and the fluorescence intensity of hypercholesterolemia serum are both higher than those of normal human serum. Besides, there are new absorptive peaks and new fluorescence peaks in the spectrogram. Thus, the abnormalism of cholesterol in serum can be judged by comparing the absorption and fluorescence spectra. The researches in the present paper provide an experimental foundation for the diagnosis of cholesterol in blood.

Blood Chemical Analysis↗
PubMed2006

[Sperm sex chromosome analysis and preimplantation genetic diagnosis of patients with sex chromosome anomalies].

OBJECTIVE: To investigate the constitution of abnormal spermatozoa from patients with sex chromosome anomalies. METHODS: Triple color fluorescence in situ hybridization (FISH) was used to determine the sex chromosome constitution of spermatozoa from three patients with sex chromosome anomalies (case 1:46,XY/47,XXY, case 2:45,XO/46,X,Yqh-, case 3:47,XXY). The preimplantation genetic diagnosis (PGD) was performed to case 2. RESULTS: An increased ratio (2.05 vs 1) of X-bearing to Y-bearing spermatozoa was only observed in case 2, who also had an increased incidence of total abnormal spermatozoa (29.71%). An increased incidence of total abnormal spermatozoa (4.91%) was also observed in case 3. Among the constitution of abnormal spermatozoa, case 2 had the increased proportions of XY18 disomy, O18 monosomy and XO monosomy, while case 3 had an increase proportion of XY18 disomy (1.87%). PGD was performed to case 2 and one embryo with XX1818 was selected for implanting. CONCLUSION: Using FISH to detect the sperm sex chromosomes in patients with sex chromosome anomalies can provide the useful information to evaluate the risk of sex chromosome anomalies in preimplantation embryos.

Adult↗
PubMed2006

[8B7 spectrin--a new member of spectrin family].

OBJECTIVE: To analyze the nature of the protein encoded by 8B7cDNA (1 835 bp) and to examine the localization of the protein in cells. METHODS: The nature of the protein was analyzed using Blastn, Blastp, and TMpred. Expressions of 8B7 mRNA in tissues and cells were examined by Northern blotting. Recombinant expression vectors for localization test were constructed and transfected into COS-7 cells. Fluorescence emission in cells was examined upon a laser scan confocal microscope. RESULTS: The protein encoded by 8B7cDNA was 363 amino acids long and contained spectrin repeats. It was completely homologous to the C-terminal 363 amino acids of Enaptin, Nasprin-1, Mynel, and Syne-1 proteins. It belonged to Spectrin super-family and was called 8B7 spectrin. Northern blotting revealed a 1.8 kb mRNA expression in human spleen and small intestine tissues. EGFP-8B7 fusion protein was observed to express on the nuclear membrane and in the cytoplasm in a reticular form in a localization assay on COS-7 cells. The position of fluorescence in COS-7 cells transfected with pEGFP-delta SR8B7 was similar to that in the cells transfected with pEGFP-8B7cDNA. CONCLUSIONS: 8 B7 spectrin is a novel member of spectrin super-family. It localizes to the nuclear membrane and the cytoplasm in a reticular form in COS-7 cells. The localization is determined by the C-terminal KASH domain in 8B7 spectrin molecule.

Amino Acid Sequence↗
PubMed2005

PCR and oligonucleotide array for detection of Enterobacter sakazakii in infant formula.

Enterobacter sakazakii has been implicated in a several form of neonatal meningitis with a high mortality rate. In the present study, the species-specific PCR and oligonucleotide array assays were developed to detect the 16S-23S rDNA internal transcribed spacer (ITS) of E. sakazakii. Two pairs of specific PCR primers and 10 oligonucleotide probes were designed by sequencing the ITS of six strains of E. sakazakii and BLAST of GenBank. The specificity and efficiency of the PCR and oligonucleotide array methods were tested against a panel of numerous strains from 88 different bacterial strains. All of the E. sakazakii strains generated positive signal, and no cross-reaction was observed with non-E. sakazakii strains in the PCR and oligonucleotide array detections based on ITS sequences. Sensitivity of the detections is 1.3 CFU/100 g infant formula with the selective enrichment. Both of the PCR and oligonucleotide array procedures take only 48 h including the enrichment culture, whereas the conventional methods required at least 5 days. This study demonstrated that both of the pathogenic detections are time-saved and reliable.

Cronobacter sakazakii↗
PubMed2005

IRAS, a candidate for I1-imidazoline receptor, mediates inhibitory effect of agmatine on cellular morphine dependence.

Agmatine, an endogenous ligand for the I1-imidazoline receptor, has previously been shown to prevent morphine dependence in rats and mice. To investigate the role of imidazoline receptor antisera-selected protein (IRAS), a strong candidate for I1R, in morphine dependence, two CHO cell lines were created, in which mu opioid receptor (MOR) was stably expressed alone (CHO-mu) or MOR and IRAS were stably co-expressed (CHO-mu/IRAS). After 48 h administration of morphine (10 microM), naloxone induced a cAMP overshoot in both cell lines, suggesting cellular morphine dependence had been produced. Agmatine (0.1-2.5 microM) concentration-dependently inhibited the naloxone-precipitated cAMP overshoot when co-pretreated with morphine in CHO-mu/IRAS, but not in CHO-mu. Agmatine at 5-100 microM also inhibited the cAMP overshoot in CHO/mu and CHO-mu/IRAS. Efaroxan, an I1R-preferential antagonist, completely blocked the effect of agmatine on the cAMP overshoot at 0.1-2.5 microM in CHO-mu/IRAS, while partially reversing the effects of agmatine at 5-100 microM. L-type calcium channel blocker nifedipine entirely mimicked the effects of agmatine at high concentrations on forskolin-stimulated cAMP formation in CHO-mu and naloxone-precipitated cAMP overshoot in morphine-pretreated CHO-mu. Therefore, IRAS, in the co-transfected CHO-mu/IRAS cell line, appears necessary for low concentrations of agmatine to cause attenuation of cellular morphine dependence. An additional effect of agmatine at higher concentrations seems to relate to both transfected IRAS and some naive elements in CHO cells, and L-type voltage-gated calcium channels are not ruled out. This study suggests that IRAS mediates agmatine's high affinity effects on cellular morphine dependence and may play a role in opioid dependence.

Agmatine↗
PubMed2005

A single pair of acidic residues in the kinase major groove mediates strong substrate preference for P-2 or P-5 arginine in the AGC, CAMK, and STE kinase families.

Most basophilic serine/threonine kinases preferentially phosphorylate substrates with Arg at P-3 but vary greatly in additional strong preference for Arg at P-2 or P-5. The structural basis for P-2 or P-5 preference is known for two AGC kinases (family of protein kinases A, G, and C) in which it is mediated by a single pair of acidic residues (PEN+1 and YEM+1). We sought a general understanding of P-2 and P-5 Arg preference. The strength of Arg preference at each position was assessed in 15 kinases using a new degenerate peptide library approach. Strong P-2 or P-5 Arg preference occurred not only in AGC kinases (7 of 8 studied) but also in calmodulin-dependent protein kinase (CAMK, 1 of 3) and Ste20 (STE) kinases (2 of 4). Analysis of sequence conservation demonstrated almost perfect correlation between (a) strong P-2 or P-5 Arg preference and (b) acidic residues at both PEN+1 and YEM+1. Mutation of two kinases (PKC-theta and p21-activated kinase 1 (PAK1)) confirmed critical roles of both PEN+1 and YEM+1 residues in determining strong R-2 Arg preference. PAK kinases were unique in having exceptionally strong Arg preference at P-2 but lacking strong Arg preference at P-3. Preference for Arg at P-2 was so critical to PAK recognition that PAK1 activity was virtually eliminated by mutating the PEN+1 or YEM+1 residues. The fact that this specific pair of acidic residues has been repeatedly and exclusively used by evolution for conferring strong Arg preference at two different substrate positions in three different kinase families implies it is uniquely well suited to mediate sufficiently good substrate binding without unduly restricting product release.

Amino Acid Sequence↗
PubMed2005

Real time PCR using TaqMan and SYBR Green for detection of Enterobacter sakazakii in infant formula.

Enterobacter sakazakii is an emerging pathogen that causes meningitis, bacteremia, sepsis, and necrotizing enterocolitis in neonates and children. Powdered milk-based infant formulas have been associated with the E. sakazakii-related outbreaks in premature or other immunocompromised infants. In this study, we developed two real time PCR assays using TaqMan and SYBR Green to identify the pathogen after selective enrichment in mLST and BHI. The accuracy of two detections was tested by 35 strains of E. sakazakii and 88 non-E. sakazakii bacterial strains. The results showed that all of these E. sakazakii strains were positive reaction to the detections and all of the non-E. sakazakii strains were negative. The newly developed assays enable us to detect 1.1 CFU/100 g infant formula. And both of the assays can be accomplished within 2 business days. Compared to the traditional detection, the real time PCR procedures are quicker and simpler. In this study, we also developed a new method to design the primers, which can support multiple real time PCR with one pair of primers in SYBR Green detection. The detection methods are more sensitive and effective based on Two-Tm-Value of PCR.

Animals↗
PubMed2005

Inferring protein-protein interactions through high-throughput interaction data from diverse organisms.

MOTIVATION: Identifying protein-protein interactions is critical for understanding cellular processes. Because protein domains represent binding modules and are responsible for the interactions between proteins, computational approaches have been proposed to predict protein interactions at the domain level. The fact that protein domains are likely evolutionarily conserved allows us to pool information from data across multiple organisms for the inference of domain-domain and protein-protein interaction probabilities. RESULTS: We use a likelihood approach to estimating domain-domain interaction probabilities by integrating large-scale protein interaction data from three organisms, Saccharomyces cerevisiae, Caenorhabditis elegans and Drosophila melanogaster. The estimated domain-domain interaction probabilities are then used to predict protein-protein interactions in S.cerevisiae. Based on a thorough comparison of sensitivity and specificity, Gene Ontology term enrichment and gene expression profiles, we have demonstrated that it may be far more informative to predict protein-protein interactions from diverse organisms than from a single organism. AVAILABILITY: The program for computing the protein-protein interaction probabilities and supplementary material are available at http://bioinformatics.med.yale.edu/interaction.

Binding Sites↗
PubMed2005

Inhibition by agmatine on morphine-induced conditioned place preference in rats.

Our previous studies demonstrated the ability of exogenous agmatine to inhibit tolerance to and physical dependence on morphine in mice, rats and monkeys. The present study further evaluated the effect of agmatine on the psychological dependence induced by morphine in conditioned place preference assay. Agmatine (0.75-20 mg/kg, s.c.) co-administered with morphine during the conditioning sessions completely abolished the acquisition of morphine-induced conditioned place preference in rats, which was associated with activation of imidazoline receptors. Agmatine (0.75-10 mg/kg, s.c.) administered on the test day inhibited the expression of the place preference. After 30 days of extinction of conditioned place preference, agmatine 2.5 and 40 mg/kg inhibited the priming effect of morphine 0.5 mg/kg on the place preference. Furthermore, agmatine inhibited the increased expression of FosB in the nucleus accumbens caused by chronic morphine. All these results suggest that agmatine could inhibit morphine-induced psychological dependence and relapses by affecting the expression of transcription factor FosB.

Agmatine↗
PubMed2005

Exceptional disfavor for proline at the P + 1 position among AGC and CAMK kinases establishes reciprocal specificity between them and the proline-directed kinases.

To precisely regulate critical signaling pathways, two kinases that phosphorylate distinct sites on the same protein substrate must have mutually exclusive specificity. Evolution could assure this by designing families of kinase such as basophilic kinases and proline-directed kinase with distinct peptide specificity; their reciprocal peptide specificity would have to be very complete, since recruitment of substrate allows phosphorylation of even rather poor phosphorylation sites in a protein. Here we report a powerful evolutionary strategy that assures distinct substrates for basophilic kinases (PKA, PKG and PKC (AGC) and calmodulin-dependent protein kinase (CAMK)) and proline-directed kinase, namely by the presence or absence of proline at the P + 1 position in substrates. Analysis of degenerate and non-degenerate peptides by in vitro kinase assays reveals that proline at the P + 1 position in substrates functions as a "veto" residue in substrate recognition by AGC and CAMK kinases. Furthermore, analysis of reported substrates of two typical basophilic kinases, protein kinase C and protein kinase A, shows the lowest occurrence of proline at the P + 1 position. Analysis of crystal structures and sequence conservation provides a molecular basis for this disfavor and illustrate its generality.

Biotinylation↗
PubMed2005

Protein kinase specificity. A strategic collaboration between kinase peptide specificity and substrate recruitment.

Specificity of phosphorylation by protein kinases is essential to the integrity of biological signal transduction. Specificity is determined by two critical elements: (1) peptide specificity of the kinase, i. e., preferential phosphorylation of S/T/Y residues surrounded by particular patterns of amino acids; and (2) recruitment, i. e., increasing the frequency of encounter between kinase and substrate. Historically, the importance of peptide specificity was studied first, but it has been somewhat overshadowed by emerging emphasis on the importance of recruitment. Recent studies confirm and extend understanding of the relative contribution of these two elements. Peptide specificity always constrains the range of sites that can be phosphorylated by a kinase. Only when recruitment is very strong, as in the case with autophosphorylation, can markedly suboptimal substrates be phosphorylated.

Amino Acid Sequence↗
PubMed2005

Expression of cellular oncogene Bcl-xL prevents coronavirus-induced cell death and converts acute infection to persistent infection in progenitor rat oligodendrocytes.

Murine coronavirus mouse hepatitis virus (MHV) causes persistent infection of the central nervous system (CNS) in rodents, which has been associated with demyelination. However, the precise mechanism of MHV persistence in the CNS remains elusive. Here we show that the progenitor oligodendrocytes (central glial 4 [CG-4] cells) derived from newborn rat brain were permissive to MHV infection, which resulted in cell death, although viral replication was restricted. Interestingly, treatment with fetal bovine serum or exogenous expression of cellular oncogene Bcl-xL prevented CG-4 cells from MHV-induced cell death. Significantly, overexpression of Bcl-xL alone was sufficient to convert acute to persistent, nonproductive infection in CG-4 cells. This finding indicates that intracellular factors rather than viral components play a critical role in establishing viral persistence in CNS cells. Although viral genomic RNAs continuously persisted in Bcl-xL-expressing CG-4 cells over 10 passages, infectious virus could no longer be isolated beyond 2 passages of the cell. Such a phenomenon resembles the persistent MHV infection in animal CNS. Thus, the establishment of a persistent, nonproductive infection in CG-4 cells may provide a useful in vitro model for studying viral persistence in animal CNS. The data also suggest that direct virus-host cell interaction is one of the underlying mechanisms that regulate viral persistence in CNS cells.

Acute Disease↗