Biomedical subjects

Wei Zhu

Publications and source records attributed to Wei Zhu.

At least 55 records · Page 3Linked to original sources

PubMed2006

Implications of cancer stem cells in the treatment of cancer.

Identification of cancer stem cells (CSCs) in both hematological and solid malignancies suggests that CSCs may be a common phenomenon for most malignancies. Similarly to normal stem cells, CSCs can self-renew and differentiate into progeny cancer cells. Almost all current therapy against cancer targets differentiated cancer cells. CSCs are more resistant to therapy secondary to quiescence, increased expression of antiapoptotic proteins and drug efflux transporters. In this article, we review the current status of CSC research and propose the targeting of CSC cell-surface molecules, signal transduction pathways, the stem cell niche, stem cell differentiation and drug resistance.

Antineoplastic Agents↗

PubMed2006

[Occupational stress and job burnout in doctors].

OBJECTIVE: To investigate the status of job burnout in doctors and its relationship with occupational stress. METHODS: A total of 561 doctors from three provincial hospitals were randomly selected. The Maslach Burnout Inventory-General Survey (MBI-GS) was used to identify job burnout. The occupation stress inventory revised edition (OSI-R) was used to evaluate the level of occupational stress. RESULTS: Surgeon and doctors working in the internal medicine wards scored significantly higher in job burnout than their colleagues (P < 0.05). The 30-40 years of age group scored highest in exhaustion. The score of professional efficacy decreased with age and increased with educational levels. Role overload, responsibility, physical environment, reaction and self-care were major predictors for exhaustion. Role insufficiency, role overload and responsibility were major predictors for cynicism. Role insufficiency, social support and rational/cognitive were major predictors for professional efficacy. CONCLUSION: Maintaining moderate professional duty and responsibility, clearly defining job requirements, enriching leisure activities, and improving self-care ability are important measures to preventing job burnout.

Burnout, Professional↗

PubMed2006

Alcohol-, nicotine-, and cocaine-evoked release of morphine from invertebrate ganglia: model system for screening drugs of abuse.

BACKGROUND: Invertebrates express regulatory receptors, transporters, and channels responsive to established drugs of abuse, many of which mediate their effects through catecholamine pathways. We hypothesized that invertebrate neural systems may serve as models by which to evaluate the interactive pharmacological effects of these agents. MATERIAL AND METHODS: Ex vivo pharmacological trials determined the effects of saturating levels of ethanol on morphine levels in pooled Mytilus edulis ganglia via HPLC coupled to electrochemical detection and/or HPLC/RIA analyses. Additional trials evaluated the ability of ethanol, nicotine, and cocaine, to promote evoked release of 125I-labeled morphine from neural tissues, because intrinsically low levels of morphine did not allow direct quantification of its release. RESULTS: Incubation of pooled M. edulis pedal ganglia with 200 mM ethanol (approximately 1% ethanol v/v) resulted in a two-fold increase in morphine concentration at 15 min, return to baseline at 30 min, and a 50% decrease in morphine concentration at 60 min. Separate incubations of pooled M. edulis pedal ganglia and H. americanus nerve cord with ethanol, cocaine, and nicotine resulted in a statistically significant enhancement of 125I-trace labeled morphine release. CONCLUSIONS: The stimulatory effects of ethanol, nicotine, and cocaine on cellular expression and release of endogenous morphine suggest convergent mechanisms underlying the reinforcing and addictive properties for a variety of drugs of abuse. The evolutionary conservation of L-tyrosine as a common precursor to catecholamine and opiate/opioid signaling systems may define a functional triad involving endogenous morphine, dopamine, and other classes of addictive drugs.

Animals↗

PubMed2006

A multicenter, randomized trial of long-acting octreotide for the optimum prevention of chemotherapy-induced diarrhea: results of the STOP trial.

Diarrhea is a well-recognized side effect of chemotherapy and can result in chemotherapy delay and/or dose reduction, potentially reducing the therapeutic benefit of treatment. Octreotide has been shown to be effective in controlling chemotherapy-induced diarrhea (CID). In this open-label, randomized, multicenter study, designed to asses the effects of two dose levels of octreotide long-acting release (LAR), patients with active or prior CID and scheduled for chemotherapy were randomized to receive up to six doses of either 30 or 40 mg of octreotide LAR. The primary endpoint was the proportion of patients experiencing severe diarrhea during the trial. Secondary endpoints included the proportion of patients requiring IV fluids due to diarrhea, unscheduled visits to healthcare professionals due to diarrhea, and changes in primary therapy, as well as treatment satisfaction and quality of life. In total, 147 patients were randomized and received at least 1 dose; 124 patients were efficacy-evaluable. Baseline characters were balanced in the 30-mg and 40-mg groups with the exception of gender. Fewer patients in the 40-mg group compared with those in the 30-mg group experienced severe diarrhea (61.7% vs 48.4%; P = 0.14), required IV fluid (31.7% vs 18.8%; P = 0.10), and had diarrhea-related unscheduled healthcare visits (41.7% vs. 28.1 %; P = 0.11); however, these differences were not statistically significant. No significant differences were observed between the treatment groups in either measured quality of life or treatment satisfaction. Adverse events were balanced between the two groups. No specific recommendations can be made from this trial regarding the use of 30 mg versus 40 mg of octreotide LAR for CID.

Antidiarrheals↗

PubMed2006

[Job burnout and contributing factors for nurses].

OBJECTIVE: To investigate the degree of job burnout and contributing factors for nurses. METHODS: A total of 495 nurses from three provincial hospitals were randomly selected. The MBI-GS, EPQ-RSC and OSI-R were administered to measure job burnout, personality traits and occupational stress, respectively. RESULTS: The medical and surgical nurses had significant greater scores of job burnout than others (P < 0.05). The poorer educational background was correlated with lower professional efficacy. The younger nurses had stronger feeling of job burnout. The scores of job burnout changed with different personality traits. The main contributing variables to exhaustion were overload, sense of responsibility, role insufficient and self-care (P < 0.05). The main contributing variables to cynicism were role insufficiency, role boundary, sense of responsibility and self-care (P < 0.05). The main contributing variables to professional inefficacy were role insufficiency, social support and rational/cognitive coping (P < 0.05). CONCLUSION: Job burnout for nurses can be prevented by reducing or keeping moderate professional duties and responsibility, making clearer job descriptions, promoting leisure activities, and enhancing self-care capabilities.

Adaptation, Psychological↗

PubMed2006

Cholinergic regulation of endogenous morphine release from lobster nerve cord.

BACKGROUND: Invertebrate nervous systems are regulated by G-coupled protein receptors, chemical transporters, and ion channels responsive to established drugs of abuse including opiates, alcohol, psychostinulants, and nicotine. Thus, invertebrate nervous tissue preparations can be used as predictive model systems by which to evaluate underlying pharmacological mechanisms of addictive processes. MATERIAL/METHODS: Ex vivo pharmacological trials were used to determine the comparative effects of the nicotinic agonists and antagonists on the evoked release of labeled morphine from H. americanus nerve cord. The intrinsically low basal levels of endogenous morphine required that we utilize an ex vivo model system involving pre-labeling of intracellutlar opiate alkaloid pools with high specific activity 125I labeled morphine. RESULTS: Both nicotine and epibatidine promoted evoked release of 125I labeled morphine that is selectively linked to activation of invertebrate nicotinic receptors based on pharmacological inhibition by alpha bungarotoxin (alpha-BuTx). Epibatidine promoted release at concentrations 2-3 orders of magnitude higher than nicotine. Co-administration of nicotine (60 nM) and the pre-junctional ganglionic nicotinic antagonist hexamethonium (1 microM) produced a marked potentiation of 125I labeled morphine release; a pharmacological effect also observed for epibatidine (35 microM) co-administered with the competitive nicotinic antagonist chlorisondaminie at 1 microM. The stimulatory effects of ethanol to promote enhanced release of endogenous morphine were not affected by co-admninistration of alpha-BuTx at 1 microM. CONCLUSIONS: The stirmulatory effects of nicotine on cellular expression and release of endogenous morphine occurs via specific alpha-BuTx sensitive receptors, suggesting a novel mechanism underling the reinforcing and addictive properties of nicotine via endogenous morphine.

Animals↗

PubMed2006

Histological type of oncogenity and expression of cell cycle genes in tumor cells from human mesenchymal stem cells.

In previous experiments, a novel tumor cell line, which was characterized by dominated F6 mutated from human mesenchymal stem cells (hMSCs), was developed. The mechanism and biological characteristics of this mutation are still unclear. In this study, the histological type of F6 cells was investigated by immunohistochemistry with specific markers: vimentin, CD117, desmin, NSE and vWF. The characteristics of proliferation and metastasis were shown by PCNA (proliferating cell nuclear antigen), and nm23 and cell cycle-related genes, such as p16, p21, p53 and pRb, were analyzed by RT-PCR and immunohistochemistry. The expression of hTRAP and BMI-1 were detected by real-time PCR and Western blotting. The activity of telomerase was analyzed by TRAP (telomerase repeat amplification protocol) assay. The results showed that multi-directional differentiation occurred in F6 cells, i.e., special markers of muscle, endothelial cell and nerve system were co-expressed in F6 cells, while hardly expressed in hMSCs. F6 cells maintained the same properties as of MSCs, such as negativity for both CD117 and vimentin. F6 cells exhibited strong positivity for PCNA and negativity for nm23. The cell cycle-related genes, such as p16, p21, p53 and pRb, were not detected in F6 cells, while the expression of hTRAP and BMI-1 was significantly higher. The activity of telomerase was also significantly higher in F6 cells than that in hMSCs. These findings indicated that multi-directional differentiation occurred during the transformation of hMSCs into F6 cells, and that the genes of cell cycle and cell senescence may also be associated with the neoplasia of adult stem cells.

Acid Phosphatase↗

PubMed2006

[Construction and utilization of the prognostic model of serous ovarian adenocarcinoma].

OBJECTIVE: To analyze the related factors with prognosis in patients with serous ovarian adenocarcinoma and to set up a prognostic model of serous ovarian adenocarcinoma. METHODS: The clinical, pathological and follow-up data of 104 cases with serous ovarian adenocarcinoma were retrospectively analyzed. Kaplan-meier univariate analysis was used to screen the prognostic factors; COX univariate and multivariate analyses were used to determine the risk coefficient of each factors and different layers in each factor. Pearson rank correlation was used to reject the influence of different factors with each other. And the prognostic model of serous ovarian adenocarcinoma was set up based on the result of the above study, which could be used to deduce the survival probability of patients with serous ovarian adenocarcinoma. RESULTS: International Federation of Gynecology and Obstetrics (FIGO) stage (P = 0.0029), histological grade (P = 0.0054), residual disease (P = 0.0000), metastasis of lymph nodes (P = 0.0000) and chemotherapy (P = 0.0000) were the related factors of prognosis in patients with serous ovarian adenocarcinoma, of which FIGO stage was the most important one, followed sequentially by histological grade, metastasis of lymph node, residual disease and chemotherapy (the independent risk coefficient of each factor was 1.3392, 0.9206, 0.7071, 0.6004, 0.4985 in sequence). We set up a prognosis model according to the prognostic index of each factors. The effect of chemotherapy and residual disease on prognosis could be quantified by this model, and the higher the score, the lower the survival probability of patients. CONCLUSIONS: FIGO stage, histological grade, residual disease, metastasis of lymph nodes and chemotherapy are important prognostic factors of serous ovarian adenocarcinoma. This model can be used to estimate the prognosis of patients with serous ovarian adenocarcinoma, and the effect of both chemotherapy and residual disease on the prognosis could be quantified by the model.

Adult↗

PubMed2005

A formal [3+2] cycloaddition process with nonactivated aziridines to polysubstituted indolizidines.

[chemical reaction: see text]. Heating a mixture of ethyl 7-iodo-2-heptynoate (or its analogues), 2-aryl aziridines, and K2CO3 in dry CH(3)CN delivers polysubstituted indolizidines. This reaction goes through an S(N)2/formal [3+2] cycloaddition process and represents the first synthetically useful example of the formal [3+2] cycloaddition process through a C-N bond cleavage of nonactivated aziridines.

Journal Article↗

PubMed2005

Human white blood cells synthesize morphine: CYP2D6 modulation.

Human plasma contains low, but physiologically significant, concentrations of morphine that can increase following trauma or exercise. We now demonstrate that normal, human white blood cells (WBC), specifically polymorphonuclear cells, contain and have the ability to synthesize morphine. We also show that WBC express CYP2D6, an enzyme capable of synthesizing morphine from tyramine, norlaudanosoline, and codeine. Significantly, we also show that morphine can be synthesized by another pathway via l-3,4-dihydroxyphenylalanine (L-DOPA). Finally, we show that WBC release morphine into their environment. These studies provide evidence that 1) the synthesis of morphine by various animal tissues is more widespread than previously thought and now includes human immune cells. 2) Moreover, another pathway for morphine synthesis exists, via L-DOPA, demonstrating an intersection between dopamine and morphine pathways. 3) WBC can release morphine into the environment to regulate themselves and other cells, suggesting involvement in autocrine signaling since these cells express the mu3 opiate receptor subtype.

Base Sequence↗

PubMed2005

The homeodomain transcription factor Irx5 establishes the mouse cardiac ventricular repolarization gradient.

Rhythmic cardiac contractions depend on the organized propagation of depolarizing and repolarizing wavefronts. Repolarization is spatially heterogeneous and depends largely on gradients of potassium currents. Gradient disruption in heart disease may underlie susceptibility to fatal arrhythmias, but it is not known how this gradient is established. We show that, in mice lacking the homeodomain transcription factor Irx5, the cardiac repolarization gradient is abolished due to increased Kv4.2 potassium-channel expression in endocardial myocardium, resulting in a selective increase of the major cardiac repolarization current, I(to,f), and increased susceptibility to arrhythmias. Myocardial Irx5 is expressed in a gradient opposite that of Kv4.2, and Irx5 represses Kv4.2 expression by recruiting mBop, a cardiac transcriptional repressor. Thus, an Irx5 repressor gradient negatively regulates potassium-channel-gene expression in the heart, forming an inverse I(to,f) gradient that ensures coordinated cardiac repolarization while also preventing arrhythmias.

Action Potentials↗

PubMed2005

Mesenchymal stem cells derived from bone marrow favor tumor cell growth in vivo.

Mesenchymal stem cells (MSCs) have generated a great deal of interest in clinical application because of their potential use in regenerative medicine and tissue engineering. However, the therapeutic application of MSCs still remain limited unless the favorable effect of MSCs for tumor growth in vivo and the long-term safety of the clinical applications of MSCs are better understood. In this study, MSCs derived from fetal bone marrow (FMSCs) and adult MSCs (AMSCs) alone or FMSCs and AMSCs with tumor cell line (F6 or SW480) together were transplanted subcutaneously into BALB/c-nu/nu mice to observe the outgrowth of tumor, and the characteristics of tumor cells were investigated by pathological and immunohistochemical methods, flow cytometry and real-time quantitative PCR. The results showed that both FMSCs and AMSCs could favor tumor growth in vivo. The pathologic examination revealed that tumor tissues had rich vessel distribution, extensive necrosis and invasion surrounding normal tissues, such as muscular tissue and subcutaneous tissue. In the immunohistochemical examination, tumor cells mixed with MSCs transplanted subcutaneously exhibited elevated capability of proliferation, rich angiogenesis in tumor tissues and highly metastatic ability. To understand whether MSCs affected the general properties of the tumor cells in vivo, the expression of some surface antigens and Bmi-1 gene of tumor tissue cells was detected in this study. The results indicated that these parameters were not affected after the interaction of MSCs with tumor cells in vivo. These findings suggested that MSCs could favor tumor growth in vivo. It is necessary to carry out a study for assurance of the long-term safety before MSCs were used as a therapy tools in regenerative medicine and tissue engineering.

Adult↗

PubMed2005

Relationship of human leukocyte antigen class II genes with the susceptibility to hepatitis B virus infection and the response to interferon in HBV-infected patients.

AIM: To study the relationship of human leukocyte antigen (HLA)-DRB1 and -DQB1 alleles with the genetic susceptibility to HBV infection and the response to interferon (IFN) in HBV-infected patients. METHODS: Low-resolution DNA typing kit was used to determine HLA-DR-1 and -DQB1 genes in 72 patients with chronic hepatitis B (CHB) and HLA-DRB1 in 200 healthy people ready to donate their bone marrow in Shanghai. Among CHB patients, 35 were treated with IFNalpha-1b for 24 wk. RESULTS: The frequencies of HLA-DRB1*06, DRB1*08 and DRB1*16 alleles in 72 patients were higher than in 200 healthy people (2.08% vs 0%, OR = 3.837, P = 0.018; 11.11% vs 5.50%, OR = 2.148, P = 0.034; and 6.94% vs 3.00%, OR = 0.625, P = 0.049, respectively); whereas that of DRB1*07 allele was lower (2.78% vs 7.75%, OR = 0.340, P = 0.046). The frequency of HLA-DRB1* 14 allele was higher in 11 responders to IFN compared with 24 non-responders (18.18% vs 2.08%, OR = 10.444, P = 0.031), whereas that of DQB1*07 allele was inverse (9.09% vs 37.50%, OR = 0.167, P = 0.021). CONCLUSION: The polymorphism of HLA class II may influence the susceptibility to HBV infection and the response to IFN in studied CHB patients. Compared with other HLA-DRB1 alleles, HLA-DRB1*06, DRB1*08, and DRB1*16 may be associated with chronicity of HBV infection, HLA-DRB1*07 with protection against HBV infection, and HLA-DRB1*14 allele may be associated with a high rate of the response of CHB patients to IFN treatment. Compared with other HLA-DQB1 alleles, HLA-DQB1*07 may be associated with low response rate to IFN.

Adult↗

PubMed2005

A one-pot formal [4 + 2] cycloaddition approach to substituted piperidines, indolizidines, and quinolizidines. total synthesis of indolizidine (-)-209I.

[reaction: see text] Heating a mixture of substituted N-benzyl gamma-chloropropylamines, conjugated alkynoates or alkynones, sodium carbonate, and a catalytic amount of sodium iodide in i-PrOH at 70-83 degrees C delivers substituted piperidines in good yields. This transformation goes through a cascade Michael addition/alkylation process and represents a facile one-pot formal [4 + 2] cycloaddition approach to piperidine ring. Using secondary cyclic gamma-chloropropylamines as substrates, this process produces substituted indolizidines or quinolizidines. On the basis of this approach, indolizidine (-)-209I is elaborated in 11 steps from methyl 2-hexenoate.

Indolizines↗

PubMed2005

Sequence, annotation, and analysis of synteny between rice chromosome 3 and diverged grass species.

Rice (Oryza sativa L.) chromosome 3 is evolutionarily conserved across the cultivated cereals and shares large blocks of synteny with maize and sorghum, which diverged from rice more than 50 million years ago. To begin to completely understand this chromosome, we sequenced, finished, and annotated 36.1 Mb ( approximately 97%) from O. sativa subsp. japonica cv Nipponbare. Annotation features of the chromosome include 5915 genes, of which 913 are related to transposable elements. A putative function could be assigned to 3064 genes, with another 757 genes annotated as expressed, leaving 2094 that encode hypothetical proteins. Similarity searches against the proteome of Arabidopsis thaliana revealed putative homologs for 67% of the chromosome 3 proteins. Further searches of a nonredundant amino acid database, the Pfam domain database, plant Expressed Sequence Tags, and genomic assemblies from sorghum and maize revealed only 853 nontransposable element related proteins from chromosome 3 that lacked similarity to other known sequences. Interestingly, 426 of these have a paralog within the rice genome. A comparative physical map of the wild progenitor species, Oryza nivara, with japonica chromosome 3 revealed a high degree of sequence identity and synteny between these two species, which diverged approximately 10,000 years ago. Although no major rearrangements were detected, the deduced size of the O. nivara chromosome 3 was 21% smaller than that of japonica. Synteny between rice and other cereals using an integrated maize physical map and wheat genetic map was strikingly high, further supporting the use of rice and, in particular, chromosome 3, as a model for comparative studies among the cereals.

Arabidopsis↗

PubMed2005

In vivo and in vitro L-DOPA and reticuline exposure increases ganglionic morphine levels.

BACKGROUND: Given the presence of morphine, its metabolites and precursors, i.e., reticuline, in mammalian and invertebrate tissues, it has become imperative to determine if exposing tissues to putative opiate alkaloid and dopamine precursors would result in increasing endogenous morphine levels. MATERIAL/METHODS: Endogenous morphine levels were determined by high performance liquid chromatography coupled to electrochemical detection and radioimmunoassay, following incubation of Mytilus edulis pedal ganglia with reticuline or L-DOPA. Injection of L-DOPA or reticuline into healthy animals was via the foot. RESULTS: Ganglia incubated in vitro with reticuline or L-DOPA for 1 hour exhibited a concentration and time dependent statistically significant increase in their endogenous morphine levels (5.0 +/- 0.47, 3.6 +/- 0.45 ng/ganglion, respectively). Injection of intact, healthy animals with reticuline or L-DOPA also results in significantly higher endogenous ganglionic morphine levels. CONCLUSIONS: Taken together, we show that L-DOPA is being converted to morphine, demonstrating that pedal ganglia can synthesize morphine from these putative precursors in vitro and in vivo. This is the first demonstration of morphine being synthesized in a normal, healthy free living animal.

Alkaloids↗

PubMed2005

Human gliomas contain morphine.

BACKGROUND: Morphine has been found in cancer cell lines originating from human and animal cells. Thus, it became important to demonstrate whether or not actual tumours contain this opiate alkaloid. MATERIAL/METHODS: Human glioma tissues were biochemically treated to isolate and separate endogenous morphine via high pressure liquid chromatography (HPLC). The HPLC peak corresponding to an authentic morphine standard had its morphine level determined via radioimmune assay. The identity of this material was established by Q-TOF-MS analysis. RESULTS: Each glioma exhibited an endogenous morphine presence. Tumor extractions demonstrated a molecular mass of 286.14 da, identical to authentic morphine. Subsequent fragmentation analysis of this molecule revealed fragment masses of 129.01 da, 183.09 da and 201.07 da, corresponding to authentic morphine fragments. This material was not found in any of the solutions used in the study nor was it present as a residual material in blank HPLC runs. CONCLUSIONS: Morphine is present in human gliomas, suggesting that it may exert an action that effects tumour physiology/pathology.

Brain Neoplasms↗

PubMed2005

Determination of glutathione and glutathione disulfide in hepatocytes by liquid chromatography with an electrode modified with functionalized carbon nanotubes.

Glutathione (GSH) and glutathione disulfide (GSSG) are important thiols, which provide defence against oxidative stress by scavenging free radicals or causing the reduction of hydrogen peroxide. The ratio GSH/GSSG is often used as a sensitive index of oxidative stress in vivo. In this paper, a direct electrochemical method using an electrode modified with functionalized carbon nanotubes as electrochemical detector (ED) for liquid chromatography (LC) was described. The electrochemical behaviors of GSH and GSSG on this modified electrode were investigated by cyclic voltammetry and it was found that the functionalized carbon nanotubes exhibited efficiently electrocatalysis on the current responses of GSH and GSSG. In LC-ED, both of the analytes showed good and stable current responses. The detection limit of GSH was 0.2 pmol on column and that of GSSG was 1.2 pmol on column, which were low enough for the analysis of real small samples. The method was sensitive enough to detect difference in concentration of GSH and GSSG in hepatocytes from animals with and without introduction of oxidation stress by glucose or hydrogenperoxide.

Animals↗