Biomedical subjects

Lei Wang

Publications and source records attributed to Lei Wang.

At least 145 records · Page 8Linked to original sources

PubMed2006

Cyclin e expression and prognosis in breast cancer patients: a meta-analysis of published studies.

In vitro studies showed that cyclin E can accelerate the cell cycle by shorten the G1/S phase transition. Therefore, varieties of studies have investigated the relationship between cyclin E and survival in breast cancer patients. However, the results differed widely between studies. We reviewed the published studies and performed a meta-analysis, which including 12 independent studies and 2,534 patients. The combined HR estimate for relapse-free survival (RFS) was 2.32 (95% CI, 1.25-4.30) and 1.72 (95% CI, 0.95-3.10) in univariate and multivariate analysis, respectively. In addition, the combined HR estimate for overall survival (OS) and breast cancer specific survival (BCSS) was 2.98 (95% CI, 1.85-4.78) and 2.86 (95% CI, 1.85-4.41) in univariate and multivariate analysis, respectively. In conclusion, the high level of cyclin E appears to be an independent prognostic factor to OS/BCSS of breast cancer patients but not to RFS.

Breast Neoplasms↗

PubMed2006

In vitro effects of recombinant zebrafish IFN on spring viremia of carp virus and infectious hematopoietic necrosis virus.

In order to evaluate the effects of fish recombinant interferon (rIFN) on fish pathogenic rhabdoviruses, the zebrafish (Danio rerio) IFN (DreIFN) allele B gene was cloned and expressed in Escherichia coli. In addition, the effects of recombinant DreIFN (rDreIFN) on spring viremia of carp virus (SVCV), infectious hematopoietic necrosis virus (IHNV), and vesicular stomatitis virus (VSV) were surveyed in fish and chicken cells. The mature peptide of DreIFN allele B gene encodes 163 amino acids. Residues 3 and 98 are a pair of cysteines that likely form an intrachain disulfide bridge. rDreIFN protein was detected as a band at 21.6 kDa by SDS-PAGE. The purified rDreIFN has anti-SVCV and anti-IHNV activity of 3 x 10(4) U/mg-10(7) U/mg. The results indicate that rDreIFN has higher activity against SVCV and IHNV on epithelioma papulosum cyprinid (EPC) than on grass carp (C. idellus) ovary (CO) cell lines and no activity against VSV on chick embryo fibroblasts (CEF).

Amino Acid Sequence↗

PubMed2006

Biocompatibility of a lab-on-a-pill sensor in artificial gastrointestinal environments.

In this paper, we present a radiotelemetry sensor, designed as a lab-in-a-pill, which incorporates a two-channel microfabricated sensor platform for real-time measurements of temperature and pH. These two parameters have potential application for use in remote biological sensing (for example they may be used as markers that reflect the physiological environment or as indicators for disease, within the gastrointestinal tract). We have investigated the effects of biofouling on these sensors, by exploring their response time and sensitivity in a model in vitro gastrointestinal system. The artificial gastric and intestinal solutions used represent a model both for fasting, as well as for the ingestion of food and subsequent digestion to gastrointestinal chyme. The results showed a decrease in pH sensitivity after exposure of the sensors for 3 h. The response time also increased from an initial measurement time of 10 s in pure GI juice, to ca. 25 s following the ingestion of food and 80 s in simulated chyme. These in vitro results indicate that changes in viscosity in our model gastrointestinal system had a pronounced effect on the unmodified sensor.

Biocompatible Materials↗

PubMed2006

A Na+/H+ antiporter gene of the moderately halophilic bacterium Halobacillus dabanensis D-8T: cloning and molecular characterization.

A gene encoding a Na(+)/H(+) antiporter was cloned from a chromosomal DNA of Halobacillus dabanensis strain D-8(T) by functional complementation. Its presence enabled the antiporter-deficient Escherichia coli strain KNabc to survive in the presence of 0.2 M NaCl or 5 mM LiCl. The gene was sequenced and designated as nhaH. The deduced amino-acid sequence of NhaH consists of 403 residues with a calculated molecular mass of 43,481 Da, which was 54% identical and 76% similar to the NhaG Na(+)/H(+) antiporter of Bacillus subtilis. The hydropathy profile was characteristic of a membrane protein with 12 putative transmembrane domains. Everted membrane vesicles prepared from E. coli cells carrying nhaH exhibited Na(+)/H(+) as well as Li(+)/H(+) antiporter activity, which was pH-dependent with highest activities at pH 8.5-9.0 and at pH 8.5, respectively. Moreover, nhaH confers upon E. coli KNabc cells the ability to grow under alkaline conditions.

Amino Acid Sequence↗

PubMed2006

Functional expression of the particulate methane mono-oxygenase gene in recombinant Rhodococcus erythropolis.

In order to construct an expression system for the particulate methane mono-oxygenase (pMMO) gene (pmo), the structural gene cluster pmoCAB amplified from Methylosinus trichosporium OB3b was inserted into a shuttle vector pBS305 under the control of a dsz promoter and transformed into Rhodococcus erythropolis LSSE8-1. A stable transformant was successfully obtained using ethane as the sole carbon source. Fluorescence in situ hybridization results showed that the dsz promoter allowed the pmo genes to be transcribed in the recombinant strain. The effects of Cu2+ and Zn2+ concentrations on cell growth and pMMO activity in ethane-containing medium were examined. It was discovered that 7.5 microM Cu2+ and 1.8 microM Zn2+ were suitable to achieve high cell concentration and pMMO activity, but the amount of methanol accumulated during methane oxidation by the recombinant strain was still low.

DNA, Bacterial↗

PubMed2006

The pha2 gene cluster involved in Na+ resistance and adaption to alkaline pH in Sinorhizobium fredii RT19 encodes a monovalent cation/proton antiporter.

Sinorhizobium fredii RT19 can tolerate up to 0.6 M NaCl, whereas all its pha2-disrupted mutants, constructed by Tn5 mutagenesis, failed to grow in even the presence of 0.1 M NaCl. No growth difference was detected in pha2 mutants at a pH<7.5 in the presence or absence of K+, but growth reduction was observed in the presence of K+ when pH>7.5. The pha2 gene cluster was able to completely restore the growth of the pha2 mutants of S. fredii RT19 in 0.6 M NaCl. Measurement of monovalent cation intracellular content suggested that pha2 was involved in both Na+ (Li+) and K+ efflux. The pha2 mutants exhibited K+/H+, but no apparent Na+(Li+)/H+ antiporter activity in everted membrane vesicles. Taken together, these results indicated that the pha2 cluster of S. fredii RT19 encodes a monovalent cation/proton antiporter involved in resistance to Na+ and adaption to pH, which was very different from the pha1 cluster of Sinorhizobium meliloti, which encodes a K+/H+ antiporter.

Cation Transport Proteins↗

PubMed2006

Effective use of corticosteroids in treatment of plastic bronchitis with hemoptysis in Chinese adults.

AIM: To investigate whether corticosteroids are effective in the treatment of plastic bronchitis with hemoptysis. METHODS: A retrospective, clinical study was undertaken. Thirty two patients with only first episodes of plastic bronchitis with hemoptysis were divided into a steroid group (n=18) treated with glucocorticoids, and a non-steroid group (n=14). The supportive therapy was uniformly applied to both groups, except for glucocorticoids. Variables such as temperature and white blood cell counts were determined. Furthermore, the volume of hemoptysis and bronchial casts were evaluated in detail daily. RESULTS: There was no difference in the demographic data and variables at baseline between both groups (all P>0.05). On days 5, 6, 7 and 8, the volume of hemoptysis was significantly decreased in the steroid group compared with the non-steroid group (43+/-15 mL vs 117+/-33 mL on d 5, 29+/-12 mL vs 97+/-23 mL on d 6, 18+/-10 mL vs 80+/-20 mL on d 7, and 13+/-8 mL vs 66+/-14 mL on d 8; all P<0.05), and on d 10 after fibreoptic bronchoscopy, the cases with bronchial casts was reduced evidently in the steroid group in comparison with the non-steroid group (OR=5.69, 95% CI=1.76-43.6; P=0.005). There was no significance in mechanical ventilation and mortality between both groups. CONCLUSION: Despite some limitations of this study, it has been demonstrated that, on the basis of common supportive therapy, corticosteroids would be effective and safe for the treatment of plastic bronchitis with hemoptysis.

Adrenal Cortex Hormones↗

PubMed2006

Use of a serotype-specific DNA microarray for identification of group B Streptococcus (Streptococcus agalactiae).

Group B Streptococcus (GBS; Streptococcus agalactiae) is an important cause of sepsis and meningitis. Nine GBS serotypes, based on capsular polysaccharide (CPS) antigens, have been described. Their distribution varies worldwide and needs to be monitored to understand the epidemiology of GBS disease and inform the development of vaccines. In this study, we sequenced cpsH of GBS serotype II (cpsHII) and compared it with that of the other eight serotypes to identify serotype-specific regions. We then developed a DNA microarray based on the cpsH gene and used it to test 88 GBS isolates-9 serotype reference strains and 79 clinical isolates-and 7 other bacterial and fungal species which are commonly present in the vagina flora. The microarray was shown to be specific and reproducible. This is the first report of a microarray which can identify the nine GBS serotypes. The use of a microarray has advantages over traditional serotyping methods and will be of practical value in both reference and diagnostic laboratories.

Bacterial Capsules↗

PubMed2006

Prevention of cerebral oxidative injury by post-ischemic intravenous administration of Shengmai San.

Shengmai San (SMS) is a traditional Chinese medicine (TCM) comprising three different herbal components, Panax ginseng, Ohiopogon japonicus and Fructus schisandrae and has been used for treating coronary heart diseases (Bensky and Barolet, 1990). It was shown that SMS effectively prevented cerebral oxidative injury in rats when it administered into the duodenum before cerebral ischemia-reperfusion. In the present study, we examined whether post-ischemic administration of SMS can ameliorate cerebral ischemia-reperfusion injury in rats as well. Results showed that SMS injected immediately after ischemia also prevented the ischemia-reperfusion injury, when the effect was evaluated by the formation of protein carbonyl and thiobarbituric acid reactive substance (TBARS), and the loss of glutathione peroxidase (GPX). The preventative potential of SMS was decreased rapidly dependent on the time lag until SMS was injected after ischemia. However, it was noted that intravenously administered SMS protected the oxidative injury approximately 30% even after 60 min of reperfusion in terms of protein carbonyl formation. It is thus suggested that SMS injection might be useful for preventing the progression of injury in cerebral infarction after stroke.

Animals↗

PubMed2006

Expanding the genetic code.

Recently, a general method was developed that makes it possible to genetically encode unnatural amino acids with diverse physical, chemical, or biological properties in Escherichia coli, yeast, and mammalian cells. More than 30 unnatural amino acids have been incorporated into proteins with high fidelity and efficiency by means of a unique codon and corresponding tRNA/aminoacyl-tRNA synthetase pair. These include fluorescent, glycosylated, metal-ion-binding, and redox-active amino acids, as well as amino acids with unique chemical and photochemical reactivity. This methodology provides a powerful tool both for exploring protein structure and function in vitro and in vivo and for generating proteins with new or enhanced properties.

Amino Acid Substitution↗

PubMed2006

Soluble transferrin receptor-1 levels in mice do not affect iron absorption.

Soluble transferrin receptor-1 (sTfR1) concentrations are increased in the plasma under two conditions that are associated with increased iron absorption, i.e. iron deficiency and increased erythropoiesis. To determine the possible role of sTfR1 as a signaling mechanism for iron absorption, a hydrodynamic gene transfer technique was established to express transfected plasmid constructs of human sTfR1 (hsTfR1) and murine sTfR1 (msTfR1) from the livers of C57BL/6 mice. Iron absorption, serum iron levels and hepcidin expression were then measured. The hydrodynamic gene transfer technique proved to be an effective approach to achieving sustained expression of sTfR1 in mice. Although expression of high levels of sTfR1 significantly increased serum iron levels, repeated experiments showed that neither hsTfR1 nor msTfR1 had any effect on iron absorption or hepcidin mRNA expression levels. Thus, despite its attractiveness as a potential modifier of iron absorption, sTfR1 levels do not exert a regulatory effect on iron absorption.

Animals↗

PubMed2006

Plasma cortisol and progression of dementia in subjects with Alzheimer-type dementia.

OBJECTIVE: Studies of subjects with dementia of the Alzheimer type have reported correlations between increases in activity of the hypothalamic-pituitary-adrenal (HPA) axis and hippocampal degeneration. In this study, the authors sought to determine whether increases in plasma cortisol, a marker of HPA activity, were associated with clinical and cognitive measures of the rate of disease progression in subjects with Alzheimer-type dementia. METHOD: Thirty-three subjects with very mild and mild Alzheimer-type dementia and 21 subjects without dementia were assessed annually for up to 4 years with the Clinical Dementia Rating scale and a battery of neuropsychological tests. Plasma was obtained at 8 a.m. on a single day and assayed for cortisol. Rates of change over time in the clinical and cognitive measures were derived from growth curve models. RESULTS: In the subjects with dementia, but not in those without dementia, higher plasma cortisol levels were associated with more rapidly increasing symptoms of dementia and more rapidly decreasing performance on neuropsychological tests associated with temporal lobe function. No associations were observed between plasma cortisol levels and clinical and cognitive assessments obtained at the single assessment closest in time to the plasma collection. CONCLUSIONS: Higher HPA activity, as reflected by increased plasma cortisol levels, is associated with more rapid disease progression in subjects with Alzheimer-type dementia.

Age Factors↗

PubMed2006

Abnormalities of thalamic activation and cognition in schizophrenia.

OBJECTIVE: Functional and structural magnetic resonance imaging (MRI) was used to investigate relationships among structure, functional activation, and cognitive deficits related to the thalamus in individuals with schizophrenia and healthy comparison subjects. METHOD: Thirty-six schizophrenia subjects and 28 healthy comparison subjects matched by age, gender, race, and parental socioeconomic status underwent structural and functional MRI while performing a series of memory tasks, including an N-back task (working memory), intentional memorization of a series of pictures or words (episodic encoding), and a yes/no recognition task. Functional activation magnitudes in seven regions of interest within the thalamic complex, as defined by anatomical and functional criteria, were computed for each group. RESULTS: Participants with schizophrenia exhibited decreased activation within the whole thalamus, the anterior nuclei, and the medial dorsal nucleus. These nuclei overlap with subregions of the thalamic surface that the authors previously reported to exhibit morphological abnormalities in schizophrenia. However, there were no significant correlations between specific dimensions of thalamic shape variation (i.e., eigenvectors) and the activation patterns within thalamic regions of interest. Better performance on the working memory task among individuals with schizophrenia was significantly associated with increased activation in the anterior nuclei, the centromedian nucleus, the pulvinar, and the ventrolateral nuclei. CONCLUSIONS: These results suggest that there are limited relationships between morphological and functional abnormalities of the thalamus in schizophrenia subjects and highlight the importance of investigating relationships between brain structure and function.

Adult↗

PubMed2006

Suppression of breast cancer cell growth by Na+/H+ exchanger regulatory factor 1 (NHERF1).

INTRODUCTION: Na+/H+ exchanger regulatory factor 1 (NHERF1, also known as EBP50 or NHERF) is a putative tumour suppressor gene in human breast cancer. Located at 17q25.1, NHERF1 is frequently targeted during breast tumourigenesis. Loss of heterozygosity (LOH) at the NHERF1 locus is found in more than 50% of breast tumours. In addition, NHERF1 is mutated in a subset of primary breast tumours and breast cancer cell lines. LOH at the NHERF1 locus is strongly associated with aggressive features of breast tumours, implicating NHERF1 as a haploinsufficiency tumour suppressor gene. However, the putative NHERF1 tumour suppressor activity has not been functionally verified. METHODS: To confirm the NHERF1 tumour suppressor activity suggested by our genetic analyses, we used retrovirus-transduced short hairpin RNA (shRNA) to knock down NHERF1 expression in breast cancer cell lines MCF7 and T47D. These cells were then assessed for cell growth in vitro and in vivo. The control and NHERF1 knockdown cells were also serum-starved and re-fed to compare their cell cycle progression as measured by fluorescence-activated cell sorting analyses. RESULTS: We found that downregulation of the endogenous NHERF1 in T47D or MCF7 cells resulted in enhanced cell proliferation in both anchorage-dependent and -independent conditions compared with that of the vector control cells. NHERF1 knockdown T47D cells implanted at mammary fat pads of athymic mice formed larger tumours than did control cells. We found that serum-starved NHERF1 knockdown cells had a faster G1-to-S transition after serum re-stimulation than the control cells. Immunoblotting showed that the accelerated cell cycle progression in NHERF1 knockdown cells was accompanied by increased expression of cyclin E and elevated Rb phosphorylation level. CONCLUSION: Our findings suggested that the normal NHERF1 function in mammary epithelial cells involves blockage of cell cycle progression. Our study affirmed the tumour suppressor activity of NHERF1 in breast which may be related to its regulatory effect on cell cycle. It warrants future investigation of this novel tumour suppressor pathway in human breast cancer which may turn up therapeutic opportunities.

Animals↗

PubMed2006

Determination of chlorogenic acid in rat plasma by high performance chromatography after peritoneal administration of compound Daqingye injection.

A simple and sensitive high performance liquid chromatographic method has been developed for the determination of chlorogenic acid (3-O-caffeoyl-D-quinic acid) in rat plasma and applied to its pharmacokinetic study in rats after peritoneal administration of compound Daqingye injection. Plasma samples are extracted with perchloric acid. HPLC analysis of the chlorogenic acid is performed on a C(18) reversed-phase column using methanol-water (80: 20, v/v, pH 2.8) as mobile phase with UV detector set at 327 nm. The standard curves are linear in the range of 0.200-10.0 microg/ml (r=0.9982). The inter- and intra-day precision (relative standard deviation) was less than 9% and the accuracy (relative error) was less than 10%. The limit of quantitation was 0.200 microg/ml. The plasma concentration of chlorogenic acid shows a C(max) of 7.53+/-0.52 microg/ml at 13.33+/-4.00 min with a t(1/2) of 59.10+/-5.42 min.

Animals↗

PubMed2006

[Molecular cloning and homologous modeling of Wulong goose MHC class I gene].

Major histocompatibility complex (MHC) was correlated with immune response for extra-antigen. MHC sequences of chicken, other birds, crawl species and mammalian were derived from GenBank/DDBJ/EMBL and analyzed by alignment, and then primers were designed. By means of LA-PCR method, MHC Classgene was cloned from Wulong goose genomic DNA and total RNA, and the structure of MHC Classgenomic DNA was analyzed using bioinformation methods. The results showed that the genomic DNA, which consisted of 8 extrons and 7 introns, had 64.1% amino acids homologous to chicken and 42.9% amino acids to human. The molecular phylogenetic tree further revealed evolutionary relationship between Wulong goose and other animals such as chicken, other birds, crawl species, mammalian and human. The results of homologous modeling showed that Wulong Goose MHC Classgene was formed by amidocyanogen (N) terminal structure region and carboxyl (C) terminal structure region.

Animals↗

PubMed2006

Noninvasive detection of TMPRSS2:ERG fusion transcripts in the urine of men with prostate cancer.

We recently reported the identification of recurrent gene fusions in the majority of prostate cancers involving the 5' untranslated region of the androgen-regulated gene TMPRSS2 and the ETS family members ERG, ETV1, and ETV4. Here we report the noninvasive detection of these gene fusions in the urine of patients with clinically localized prostate cancer. By quantitative polymerase chain reaction, we assessed the expression of ERG and TMPRSS2:ERG transcripts in urine samples obtained after prostatic massage from 19 patients (11 prebiopsy and 8 pre-radical prostatectomy) with prostate cancer. We observed a strong concordance between ERG overexpression and TMPRSS2:ERG expression, with 8 of 19 (42%) patients having detectable TMPRSS2:ERG transcripts in their urine. Importantly, by fluorescence in situ hybridization, we confirmed the presence or the absence of TMPRSS2:ERG gene fusions in matched prostate cancer tissue samples from three of three patients with fusion transcripts in their urine and from two of two patients without fusion transcripts in their urine. These results demonstrate that TMPRSS2:ERG gene fusions can be detected in the urine of patients with prostate cancer and support larger studies on prospective cohorts for noninvasive detection of prostate cancer.

5' Untranslated Regions↗

PubMed2006

Determination of amino acids in tobacco samples by capillary electrophoresis/indirect absorbance detection with isolation of the electrolysis compartment and p-Aminobenzoic acid as a background electrolyte.

A fast, convenient and sensitive method of capillary zone electrophoresis (CZE) and indirect UV detection was proposed for the determination of 16 amino acids. p-Aminobenzoic acid (PAB) was selected as a background electrolyte (BGE). An isolated cell included a BGE buffer part and an electrode buffer one, which were jointed with a glass frit. The isolated cell can prevent PAB from the electrode reaction and improve the stability of the detection baseline. The separation conditions of amino acids were investigated, such as different BGEs, BGE concentration, buffer pH and electroosmotic flow (EOF) modifiers. Under the selected separation conditions, 14 amino acid peaks could be separated in 12 min. The detection limits of the amino acids were in the range of 1.7 - 4.5 micromol/L. The isolated cell is suitable for reagents reacting on the electrodes in capillary electrophoresis. The proposed method has been successfully applied to the determination of the amino acids in tobacco samples.

4-Aminobenzoic Acid↗