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Biomedical subjects

Yuan Zhou

Publications and source records attributed to Yuan Zhou.

At least 37 records · Page 2Linked to original sources
PubMed2005

Effectiveness of the derived Alcohol Use Disorders Identification Test (AUDIT-C) in screening for alcohol use disorders and risk drinking in the US general population.

BACKGROUND: The three consumption questions from the Alcohol Use Disorders Identification Test (AUDIT-C) are increasingly used as a screener for alcohol use disorders (AUDs) and risk drinking. METHODS: In a representative sample of US adults 18 years of age and older, AUDIT-C scores (derived from consumption questions embedded in a large national survey) were used to estimate sensitivity, specificity, and areas under receiver operator characteristic curves (AUROCs) for alcohol dependence, any AUD, and risk drinking. AUDs were defined according to DSM-IV criteria. For men, risk drinking was defined as consuming >14 drinks per week or >4 drinks in a single day at least once a month; for women, the weekly and daily limits were >7 drinks and >3 drinks, respectively. The derived AUDIT-C was evaluated among past-year drinkers (n = 26,946), within the total population (n = 43,093), in groups defined by age, sex, and race/ethnicity, and among pregnant women, persons attending an emergency room, and college students. RESULTS: For past-year drinkers, the AUROCs for the derived AUDIT-C were 0.887 for alcohol dependence, 0.860 for any AUD, and 0.966 for risk drinking. Scores were higher in the total population, 0.931, 0.917, and 0.981, respectively. The derived AUDIT-C performed slightly better in screening for dependence among women than men. Screening for risk drinking was better among men, probably because the third AUDIT-C question directly mirrors one of the definitions of risk drinking for men but not for women. Performance in pregnant women, past-year emergency room patients, and college students was on a par with performance in the general population. CONCLUSIONS: The derived AUDIT-C performs well in screening for AUDs and risk drinking. The use of variable cut points for men and women improves its sensitivity and specificity. Validation in a realistic screening situation, in which the AUDIT-C questions are asked as stand-alone and not embedded items, is a critical future step.

Adolescent↗
PubMed2005

[Effect of calmodulin antagonist EBB on invasion of human fibrosarcoma cell HT1080].

OBJECTIVE: To investigate the potential effect of EBB, a calmodulin antagonist, on invasion of human fibrosarcoma cells HT1080. METHODS: The antitumor effect of EBB was assessed by 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Activities of matrix metalloproteinase (MMP)-2 and MMP-9 were measured by Zymogrophy analysis. The mRNA levels, of MMP-2, MMP-9, and tissue inhibitor of metalloproteinases (TIMP)-1 were evaluated by reverse transcriptionpolymerase chain reaction (RT-PCR). Transwell chamber assay was applied to measure the effect of EBB on the invasion of HT1080 cells. RESULTS: Calmodulin antagonist EBB inhibited the proliferation of HT1080 cells with an IC50 of (8.2 +/- 1.2) microg/ml. EBB down-regulated the activities of MMP-2 and MMP-9, and down-regulated the mRNA levels of MMP-2 and MMP-9, while up-regulated the mRNA levels of TIMP-1. The invasive ability of HT1080 cells was decreased to (31.13 +/- 2.265)%, (59.91 +/- 2.566)%, and (71.58 +/- 0.5960)% after exposure of the cells with 2, 5, and 10 microg/ml EBB, respectively. CONCLUSION: Treatment with calmodulin antagonist EBB is effective in suppressing tumor invasion. The possible mechanism is the down-regulation of MMPs.

Antineoplastic Agents↗
PubMed2005

[Clinical evaluation of intracoronary in-stent stenosis by electron-beam CT single flow mode study].

OBJECTIVE: To investigate the diagnostic accuracy and clinical value of electron-beam CT (EBCT) single flow mode study (EBCTSF) in combination with EBCT coronary angiography (EBCTCA) and three dimensional reconstruction using medial axis reformation (MAR) for diagnosis of coronary in-stent stenosis. METHODS: Electrocardiogram-gated EBCT single coronary scanning (without and with contrast medium) was performed in 25 consecutive coronary heart disease (CHD) patients during a short breathhold. EBCTSF was then performed at the level nearly distal to stent. Three-dimensional coronary images were reformed using MAR. EBCT findings were compared with that of conventional coronary angiography (CAG). RESULTS: Thirty-five intracoronary stents were implanted in thirty-one diseased vessel segments. EBCTSF procedure was unsuccessful in 2 patients (successful rate was 92.0%, 23/25). There was a significant decrease in flow peak value (Dp), increased value (Deltad) and area under curve (A), and a significant increase in prolonged peak time (Td) in stenosed stents compared to normal stents (P < 0.05). EBCTCA was successful for all patients. Seven stenosed stents (5 in left anterior descending branch and 2 in right coronary) were correctly evaluated with EBCT. Compared with CAG, EBCTSF in combination with EBCTCA images and MAR reconstruction images had a diagnostic sensitivity of 85.0% (6/7) and a specificity of 92.9% (26/28) for detecting significant in-stent stenosis (> 50% lumen diameter). Positive and negative predictive value were 75.0% (6/8) and 96.5% (26/27) respectively. Compared with EBCT cross-section images alone, or cross-section images and three-dimensional images, the diagnostic accuracy increased from 80.0% and 88.6% to 91.4% (32/35). CONCLUSIONS: Noninvasive EBCTSF can be used to quantitatively analyze coronary flow characteristics. This technique, used in combination with EBCTCA and three dimensional reconstruction using MAR, seems to be an effective imaging modality in identifying coronary in-stent stenosis. For stent-implanted patients with atypical and nonischemic chest pain after coronary intervention, the above-mentioned technique is of important value for evaluating therapeutic effect and follow-up results.

Coronary Angiography↗
PubMed2004

P2Y12 receptors play a significant role in the development of platelet microaggregation in patients with diabetes.

Ninety-eight diabetic patients (type 2) were studied together with 24 healthy normotensive controls. Microaggregates (particle scale, <25 microm) of platelets were detected by a laser scattering system. Microaggregates in the control group showed a time-dependent reversible change; however, they existed continuously in 82 of 98 diabetic patients. When platelets of diabetics were stimulated by a shear stress alone without ADP, 74 also showed spontaneous and irreversible microaggregates even though they were not observed in all control subjects. In control subjects, microaggregates were inhibited by MRS2279 (a P2Y1 antagonist), but not AR-C69931MX (a P2Y12 antagonist). However, AR-C69931MX prevented irreversible microaggregates in diabetic patients. When either aspirin or ticlopidine was administered to diabetic patients with irreversible microaggregates, both drugs significantly decreased microaggregates induced by a low dose of ADP. Ticlopidine additionally reduced the microaggregates induced by shear stress alone. In conclusion, microaggregates of platelets via P2Y12 receptors could play a key role in the hypersensitivity of platelets in diabetic patients, and the measurement of microaggregation could be a useful marker to estimate of thrombogenesis. These findings present a possible new means for patients with diabetes to prevent ischemic events.

Adenosine Diphosphate↗
PubMed2004

The use of proteomics in the discovery of serum biomarkers from patients with severe acute respiratory syndrome.

Severe acute respiratory syndrome (SARS) is a new infectious disease with a global impact. Understanding its pathogenesis and developing specific diagnostic methods for its early diagnosis are crucial for the effective management and control of this disease. By using proteomic technology, truncated forms of alpha(1)-antitrypsin (TF-alpha(1)-AT) were found to increase significantly and consistently in sera of SARS patients compared to control subjects. The result showed a sensitivity of 100% for SARS patients and a specificity of 92.8% for controls. Furthermore, the levels of these proteins significantly correlated with certain clinico-pathological parameters. The dramatic increase in TF-alpha(1)-AT may be the result of degradation of alpha(1)-AT. As alpha(1)-AT plays an important role in the protection of lung function, its degradation may be an important factor in the pathogenesis of SARS. These findings indicate that increased TF-alpha(1)-AT may be therapeutically relevant, and may also be a useful biological marker for the diagnosis of SARS.

Biomarkers↗
PubMed2004

Effects of sodium houttuyfonate on phosphorylation of CaMK II, CREB and ERK 1/2 and expression of c-Fos in macrophages.

The purpose of this research is to investigate the effects of sodium houttuyfonate on the phosphorylation of CaMK II, CREB and ERK 1/2, and the expression of c-Fos. Macrophages were cultured in vitro with or without sodium houttuyfonate in the culture medium. After cell culture, macrophages were lysed and the lysate of the macrophages was collected for analysis. Western-blotting method was adopted to investigate the phosphorylation or the expression of these signal elements. It was found in this research that the phosphorylation levels of CaMK II and CREB and the expression of c-Fos protein in macrophages were increased by sodium houttuyfonate treatment; however, the phosphorylation level of ERK 1/2 was not affected by the treatment.

Adjuvants, Immunologic↗
PubMed2004

The protective effects of ligustrazine on ischemia-reperfusion and DPPH free radical-induced myocardial injury in isolated rat hearts.

Previous investigations have suggested that tumor necrosis factor-alpha (TNF-alpha) can contribute to myocardial damage during ischemia-reperfusion. In the present study, we examined whether the cardioprotective effects of ligustrazine are related to inhibition of TNF-alpha production in the rat models of ischemia-reperfusion and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-induced myocardial injury. Ischemia for 20 min and reperfusion for 40 min caused a decline in cardiac function (left ventricular pressure, +/- d p/d t(max), heart rate and coronary flow) and an increase in the release of creatine kinase in coronary effluent and the content of TNF-alpha in myocardial tissues. Similarly, perfusion with DPPH (100 nM) for 30 min significantly decreased cardiac function, and increased the release of creatine kinase and the content of TNF-alpha. Ligustrazine at the concentration of 40 or 80 mg/L markedly improved cardiac function and reduced the release of creatine kinase and the content of TNF-alpha in myocardial tissues in hearts subjected to ischemia-reperfusion or DPPH perfusion. These results suggest that the cardioprotection afforded by ligustrazine is related to a reduction of TNF-alpha content by inhibition of free radical production in isolated rat hearts.

Animals↗
PubMed2004

[Identification of differentially expressed genes involved in multidrug resistance in K562/A02 by cDNA microarray].

OBJECTIVE: To study the molecular mechanism underlying multidrug resistance (MDR) and identify unknown genes that might be involved in drug resistance development in K562/A02 cells. METHODS: K562/A02 was induced by gradually increasing the ADM concentration in culture medium of K562 cells, the differential expression of associated genes between K562 and K562/A02 was determined with cDNA microarray. Overexpression of neurofilament protein NF-H gene in K562/A02 cells was confirmed with RT-PCR and immunocytochemistry. Anti-sense oligodeoxynucleotides were transfected into K562/A02 cells by lipofectamine in order to further analyze the role of NF-H in drug resistance. RESULTS: Comparing with the expression profiles, we found upregulation of 5 transcripts and downregulation of 7 transcripts in response to MDR of K562/A02 cells. The overexpression of NF-H, one of the 5 upregulated genes, was confirmed. After being treated with antisense oligodeoxynucleotides of NF-H and mdr1, the cellular adriamycin concentration increased significantly, but antisense NF-H alone did not have significant effect on drug resistance phenotype. CONCLUSION: The development of MDR in K562/A02 cells is multifactorial. NF-H may be involved in the drug resistance of K562/A02, which may provide a new marker of diagnosis and a new target of therapy.

Doxorubicin↗
PubMed2003

Differential expression, localization and activity of two alternatively spliced isoforms of human APC regulator CDH1.

The timely destruction of key regulators through ubiquitin-mediated proteolysis ensures the orderly progression of the cell cycle. The APC (anaphase-promoting complex) is a major component of this degradation machinery and its activation is required for the execution of critical events. Recent studies have just begun to reveal the complex control of the APC through a regulatory network involving WD40 repeat proteins CDC20 and CDH1. In the present paper, we report on the identification and characterization of human CDH1beta, a novel alternatively spliced isoform of CDH1. Both CDH1alpha and CDH1beta can bind to the APC and stimulate the degradation of cyclin B1, but they are differentially expressed in human tissues and cells. CDH1alpha contains a nuclear localization signal which is absent in CDH1beta. Intracellularly, CDH1alpha appears in the nucleus whereas CDH1beta is a predominantly cytoplasmic protein. The forced overexpression of CDH1alpha in cultured cells correlates with the reduction of nuclear cyclin A, but the steady-state amount of cyclin A does not change noticeably in CDH1beta-overexpressed cells. In Xenopus embryos, ectopic overexpression of human CDH1alpha, but not of CDH1beta, induces cell-cycle arrest during the first G(1) phase at the mid-blastula transition. Taken together, our findings document the differential expression, subcellular localization and cell-cycle-regulatory activity of human CDH1 isoforms.

Alternative Splicing↗
PubMed2003

Transcriptional regulation of yeast peroxiredoxin gene TSA2 through Hap1p, Rox1p, and Hap2/3/5p.

In Saccharomyces cerevisiae, the transcription of peroxiredoxin gene TSA2 is responsive to various reactive oxygen and nitrogen species. Redox-regulated transcriptional activators Yap1p, Skn7p, Msn2p/Msn4p have been shown to play a role in regulating TSA2 expression. In this study we show that the transcription of TSA2 is under complex control involving additional transcription factors Hap1p, Rox1p, and Hap2/3/5p. Deletion of HAP1 led to a 50% reduction of TSA2 transcriptional activity. As an intracellular oxygen sensor, heme stimulated TSA2 transcription by activating Hap1p. The induction of TSA2 by H(2)O(2) is also mediated in part through Hap1p. Countering the effects of Hap1p was a transcriptional repressor Rox1p. Deletion of ROX1 or mutation of Rox1p-binding site significantly activated TSA2 transcription. In addition, TSA2 activity was diminished in hap2Delta, hap3Delta, hap4Delta, and hap5Delta strains, but was stimulated upon overexpression of Hap4p. Hap2/3/5p may cooperate with Msn2/4p to activate TSA2 after diauxic shift. Finally, we demonstrated a role for kinases Ras1/2p and Hog1p in Msn2/4p-dependent activation of TSA2. In particular, Hog1p mediated the response of TSA2 to osmotic and oxidative stress. Taken together, our findings suggest that the expression of TSA2 is regulated by a group of transcription factors responsive differentially to stress conditions.

Antioxidants↗
PubMed2003

Nuclear localization of the cell cycle regulator CDH1 and its regulation by phosphorylation.

The anaphase-promoting complex activated by CDC20 and CDH1 is a major ubiquitination system that controls the destruction of cell cycle regulators. Exactly how ubiquitination is regulated in time and space is incompletely understood. Here we report on the cell cycle-dependent localization of CDH1 and its regulation by phosphorylation. CDH1 localizes dynamically to the nucleus during interphase and to the centrosome during metaphase and anaphase. The nuclear accumulation of CDH1 correlates with a reduction in the steady-state amount of cyclin A, but not of cyclin E. A nuclear localization signal conserved in various species was identified in CDH1, and it sufficiently targets green fluorescent protein to the nucleus. Interestingly, a CDH1-4D mutant mimicking the hyperphosphorylated form was constitutively found in the cytoplasm. In further support of the notion that phosphorylation inhibits nuclear import, the nuclear localization signal of CDH1 with two phospho-accepting serine/threonine residues changed into aspartates was unable to drive heterologous protein into the nucleus. On the other hand, abolition of the cyclin-binding ability of CDH1 has no influence on its nuclear localization. Taken together, our findings document the phosphorylation-dependent localization of CDH1 in vertebrate cells.

Amino Acid Sequence↗
PubMed2003

Serum biomarkers of hepatitis B virus infected liver inflammation: a proteomic study.

Hepatitis B virus (HBV), a serious infectious and widespread human pathogen, represents a major health problem worldwide. Chronic HBV infection has a very high risk of evolving into hepatocellular carcinoma. Although considerable progress was made during the recent past, the pathogenesis of HBV infection is still elusive and a definite diagnosis of HBV infected liver information still relies on biopsy histological test. In this report, we used proteomics technology to globally examine HBV infected serum samples aiming at searching for disease-associated proteins that can be used as serological biomarkers for diagnosis and/or target proteins for pathogenetic study. By comparing with normal and HBV negative serum samples, we found that at least seven proteins were significantly changed in HBV infected sera. These greatly altered proteins were identified to be haptoglobin beta and alpha2 chain, apolipoprotein A-I and A-IV, alpha1-antitrypsin, transthyretin and DNA topoisomerase IIbeta. The alteration of these proteins is displayed not only in quantity but also in patterns (or specificity), which can be correlated with necroinflammatory scores. In particular, apolipoprotein A-I presents heterogeneous change in expression level with different isoforms and alpha1-antitrypsin produces evidently different fragments implying diverse cleavage pathways. These unique phenomena appear specific to HBV infection. A combination simultaneously considering the quantities and isoforms of these proteins could be a useful serum biomarker (or index) for HBV diagnosis and therapy.

Adolescent↗
PubMed2003

[Determination of chlorogenic acid and eriodictyol-7-O-beta-D-glucuronide in Pyrrosia by RP-HPLC].

AIM: To develop a method for determination of chlorogenic acid and eriodictyol-7-O-beta-D-glucuronide in Pyrrosia of different species and different places of origin by RP-HPLC. METHODS: Chromatography was performed using a C18 column with mobile phase of methanol-water-phosphoric acid (50:200:0.2). The monitoring wavelength was 284 nm. RESULTS: The linear ranges were 0.01-5.0 micrograms (r = 0.9997) and 0.004-5.0 micrograms (r = 0.9997), the recoveries were 97.1% (n = 8, RSD = 2.7%) and 98.8% (n = 9, RSD = 2.5%) for chlorogenic acid and eriodictyol-7-O-beta-D-glucuronide, respectively. CONCLUSION: The method was employed to the analysis of 21 samples of Pyrrosia. The contents of compounds vary greatly depending on the species used, place of collection and time of harvesting. The HPLC method is sensitive, rapid and can be used to control the quality of Pyrrosia and to guide reasonable season of harvesting.

Chlorogenic Acid↗
PubMed2003

[Study on the absorption, distribution and excretion of 3-chloro-1,2-propandiol in rats].

OBJECTIVE: To explore the absorption, distribution and excretion of 3-Chloro-1,2-propandiol (3-MCPD) in healthy male SD rats after oral administration. METHODS: 3-MCPD was administrated with a single oral dosage of 75 mg/kg BW to each rat. Samples of blood, tissues (including liver, kidney, brain and testicle) and excreta were then collected, and analyzed by the GC-MS method to determine 3-MCPD concentrations. The reported value is the mean value of three rats. RESULTS: At 2 h after the administration, 3-MCPD concentrations in blood, testicle and kidney were (67.46 +/- 7.72), (78.37 +/- 5.15) and (56.21 +/- 3.64) microg/g, respectively. At 24 h, however, the corresponding values changed to (1.07 +/- 0.97) microg/g, (49.43 +/- 28.18) microg/g and (11.41 +/- 2.55) microg/g. During the 24-hour period, 9.74 +/- 3.05% of the given parent compound was excreted in urine, whereas 0.56 +/- 0.22% and 0.28 +/- 0.03% were excreted in feces and bile, respectively, which implies that kidney is a major organ for excretion 3-MCPD. CONCLUSIONS: 3-MCPD was quickly absorbed through the alimentary tract and quickly distributed into a number of tissues, and then accumulated in the target organs, especially in the testicle. The excretion of the parent compound was largely through the kidney. It was inferred that 3-MCPD was mainly metabolized in the liver.

Absorption↗
PubMed2003

[Effect of occupational stress on cardiovascular function of different vocational population].

OBJECTIVE: To study the effect of occupational stress on cardiovascular function of different vocational population. METHODS: The occupational stressors, risk factors of cardiovascular diseases were investigated by questionnaire in 839 people with 4 kinds of jobs. Blood pressure, sugar, and lipid were detected at the same time. RESULTS: Blood pressure were higher in the groups of old age, long standing and teachers, and the abnormal rate of blood pressure was 21.69%. There was no difference in abnormal ECG among ages, standing and occupation, and the abnormal rate of ECG was 19.07%. Job control, job demands, job responsibility, role in a job and shift work were the main stress factors affecting systolic and diastolic blood pressure. More conflict in job, less chance of participation, severe job loads were the risk factors of primary hypertension. Accident due to job responsibility, job responsibility, role in a job were the main risk factors of abnormal electrocardiograph. Self-respect and activity beyond work were the good modifiers of heart function. CONCLUSION: Occupational stress has certain effect on cardiovascular function.

Adult↗
PubMed2002

The APC regulator CDH1 is essential for the progression of embryonic cell cycles in Xenopus.

The orderly progression of cell cycle depends on timely destruction of key regulators through ubiquitin-mediated proteolysis. The anaphase-promoting complex (APC) is a major component of this degradation machinery and its activation is regulated by CDC20 and CDH1. We demonstrate here that CDH1 mRNA is ubiquitously expressed in Xenopus embryos of all developmental stages. Loss of CDH1 function during early embryonic cell cycles leads to an immediate and prolonged arrest with low cyclin-dependent kinase activity. In contrast, ectopic overexpression of CDH1 induces cell cycle arrest during the first G(1) phase at the midblastula transition. CDH1-dependent degradation of cyclin A is likely involved in this G(1) arrest. Our findings establish the essential roles of CDH1 in embryonic cell cycles.

Anaphase-Promoting Complex-Cyclosome↗
PubMed2002

Post-transcriptional suppression of gene expression in Xenopus embryos by small interfering RNA.

Double-stranded RNA (dsRNA) induces gene-specific silencing in organisms from fungi to animals, a phenomenon known as RNA interference (RNAi). RNAi represents an evolutionarily conserved system to protect against aberrant expression of genes and a powerful tool for gene manipulation. Despite reports that RNAi can be induced in vertebrates, severe sequence-non-specific effects of long dsRNA have been documented in various systems. It has recently been shown in cultured mammalian cells that small interfering RNAs (siRNAs) of 21-23 nt can mediate RNAi but bypass the non-specific response induced by longer dsRNAs. However, the effectiveness of siRNAs has not been demonstrated in living vertebrates. In addition, the mechanism of siRNA suppression of gene expression in vertebrate cells remains to be elucidated. Here we show that synthetic 21 nt siRNAs can specifically inhibit the expression of exogenously introduced as well as endogenous genes in the embryos of Xenopus laevis. siRNAs significantly reduced the steady-state amount of both the mRNA and protein of the cognate gene target. Moreover, co-injection of siRNA with the target RNA transcript specifically suppressed the activity of the latter. Taken together, our findings establish siRNA-mediated post-transcriptional suppression of gene expression in Xenopus embryos.

Animals↗