Biomedical subjects

S Zhang

Publications and source records attributed to S Zhang.

At least 55 records · Page 3Linked to original sources

PubMed2005

DNA vaccination using bacillus Calmette-Guerin-DNA as an adjuvant to enhance immune response to three kinds of swine diseases.

In order to enhance the immune efficacy of DNA vaccination, experiments were conducted to investigate the regulating effects of Bacillus Calmette-Guerin (BCG)-DNA as an adjuvant on immune responses of mice against foot-and-mouth disease (FMD), Aujeszky's disease (AjD) and classical swine fever (CSF). BCG-DNA was purified from BCG by ion-exchange chromatography. Three DNA vaccines (pVSG, pVgD and pVE2) against the respective infection were constructed, and BCG-DNA was coimmunized to mice by muscle injection. The results showed that titres of specific immunoglobulin (Ig)G to the vaccines mounted remarkably in the sera of the adjuvant covaccinated mice (P < 0.01). Antibody isotype IgG2a and IgG1 also increased, respectively, in mice coimmunized with BCG-DNA compared with those of the control groups (P < 0.01). Cellular immune cytokine interferon-gamma and cytotoxic T lymphocytes were detected in coimmunized BCG-DNA groups (P < 0.05). Whereas interleukin-4, humoral immune cytokine, was not significant (P > 0.05). These results suggest that codelivery of BCG-DNA with DNA vaccines against FMD, AjD and CSF can enhance the induction of antigen-specific, especially, cell-mediated immunity.

Adjuvants, Immunologic↗

PubMed2005

Molecular correlates of emotional learning using genetically selected rat lines.

The genetic contributions to active avoidance learning in rodents have been well established, yet the molecular basis for genetically selected line differences remains poorly understood. To identify candidate genes influencing this active avoidance paradigm, we utilized the bidirectionally selected Syracuse high- and low-avoidance (SHA and SLA) rat lines that markedly differ in their two-way active avoidance behavior. Rats were phenotyped, rested to allow recovery from testing stress and then hippocampi were dissected for gene expression profiling (Affymetrix U34A chips; approximately 7000 known genes), comparing SLA to SHA. Next, a subset of differentially expressed genes was confirmed by real-time PCR (RT-PCR) in hippocampi. Additional studies at the protein level were performed for some genes. Using triplicate arrays on pooled hippocampal samples, differentially expressed genes were identified by microarray suite 5.0 and robust multi-array average analyses. By RT-PCR analysis in hippocampi, eight genes were nominated as potential candidate genes consistent with the differential expression from the microarray data. Four genes, Veli1 (mlin-7B), SLC3a1, Ptpro and Ykt6p, showed higher expression in SHA hippocampi than SLA. Four genes, SLC6A4, Aldh1a4, Id3a and Cd74, showed higher expression in SLA hippocampi than SHA. The active avoidance behavioral difference between lines probably emerges from 'many small things'. These potential candidate genes generate hypotheses for future testing in human association and rodent studies. Differences in levels of a pleiotropic gene like Ptpro and SLC6A4 suggest that small differences over a lifespan may contribute to large behavioral differences.

Animals↗

PubMed2005

Role of the nrf-2 gene in protection and repair of gastric mucosa against oxidative stress.

Helicobacter pylori infection, as well as NSAIDs induce oxidative stress on gastric mucosa, thereby causing mucosal damage and retarding mucosal repair. Cells can survive against chronic oxidative stress by enhancing activities of anti-oxidant enzymes, thereby protecting cells from DNA damage. Recent studies have clearly shown that the gene encoding Nrf-2 (NF-E2 p45-related factor-2) plays an important role in the induction of antioxidant enzymes against oxidative stress. In this paper, we will describe the cellular mechanisms by which the nrf-2 gene stimulates anti-oxidant enzyme activities during exposure to oxidative stress. Secondly, we will also mention the beneficial effects of sulforaphane, an isothiocyanate family which is abundantly included in broccoli sprouts, on gastric mucosa. Sulforaphane stimulates nrf-2 gene-dependent anti-oxidant enzyme activities, thereby protecting cells from oxidative injury. Finally, we will state our perspective on the efficacy of sulforaphane in protection and repair of gastric mucosa against oxidative stress during H. pylori infection.

Animals↗

PubMed2005

Role of estrogen receptor (ER) alpha in insulin-like growth factor (IGF)-I-induced responses in MCF-7 breast cancer cells.

Insulin-like growth factor-I (IGF-I) is a mitogenic polypeptide that induces proliferation of MCF-7 breast cancer cells, and cotreatment with the phosphoinositide 3-kinase (PI3-K) inhibitor LY294002 and the antiestrogen ICI 182780 inhibits IGF-I-induced growth. The role of estrogen receptor alpha (ERalpha) in mediating responses induced by IGF-I was investigated in cells transfected with small inhibitory RNA for ERalpha (iERalpha). The results showed that IGF-I-dependent phosphorylation of Akt and mitogen-activated protein kinase, induction of G(1)-S-phase progression and enhanced expression of cyclin D1 and cyclin E were dependent on ERalpha. Moreover, these same IGF-I-induced responses were also inhibited by the antiestrogen ICI 182780 and this was in contrast to a previous report suggesting that ICI 182780 did not affect IGF-I-dependent activation of PI3-K or induction of cyclin D1 expression. ICI 182780 exhibits antimitogenic activity and iERalpha inhibits G(1)-S-phase progression and proliferation of MCF-7 cells treated with IGF-I, suggesting that the effects of the antiestrogen are primarily related to downregulation of ERalpha.

Base Sequence↗

PubMed2005

Trigemino-cervical response in patients with amyotrophic lateral sclerosis.

PURPOSE: The trigemino-cervical response (TCR) was investigated in the patients with amyotrophic lateral sclerosis (ALS) to evaluate its effect for disclosing the bulbar involvement in this disorder. METHODS: We studied 100 normal subjects and 45 patients with ALS. In all normal subjects, stimulation of the infraorbital nerve on one side produced bilateral short latency waves, which consisted of a positive/negative wave described with the mean peak latency (P20/N30). The mean square root of the ratio between the amplitude of P20/N30 and the mean rectified surface EMG activity preceding the stimulus was described by A value. RESULTS: The latency of P20 in controls was 18.5 +/- 1.4 ms, N30 was 28.8 +/- 2.8 ms, and the A value was 1.6 +/- 0.5, respectively. In ALS patients, twelve showed absent, seventeen were delayed in the latencies, six were above normal asymmetry on two sides, and ten showed normal. The latency of P20 in ALS patients was 22.9 +/- 9.4 ms, N30 was 33.7 +/- 11.2 ms, and the A value was 1.5 +/- 0.8, respectively. The parameters of the latencies of TCR between ALS patients and the normal controls were statistically different (P < 0.05). CONCLUSIONS: TCR can be reliably measured in all normal subjects and help in disclosing lower brainstem lesions in ALS patients, even without bulbar symptoms.

Adolescent↗

PubMed2005

An analysis of frequency response for the blood flow of volume pulse in microcirculation.

In this paper, a frequency analysis for the microcirculation model is introduced to find new microcirculation parameters in the frequency domain. By using Bode Plot of transfer function, we found two characteristic parameters of the model: damping ratio xi and break frequency omega(n). By analyzing the variation of xi and omega(n), it enables us to have better understanding of different states of microcirculation. At low damping, 0 or =1, the state of microcirculation will be worse and worse along with the descending of the omega(n). The results of experiments on 120 subjects are consistent with the analytical results of the model.

Analysis of Variance↗

PubMed2004

Dan Shen agents for acute ischaemic stroke.

BACKGROUND: Based mainly on experimental data which indicates improvement to the cerebral microcirculation, Dan Shen, a form of herbal medicine, is widely used in the treatment of acute ischaemic stroke in China. We aimed to assess the evidence from randomised controlled trials of their effects. OBJECTIVES: To review the randomised or quasi-randomised controlled trials of Dan Shen agents for acute ischaemic stroke. The primary objective was to determine whether Dan Shen agents improve functional outcome without causing undue harm in patients with acute ischaemic stroke. Secondary objectives were to assess the effect of Dan Shen agents on impairment and on quality of life. SEARCH STRATEGY: We searched the Cochrane Stroke Group Trials Register (last searched September 2003), the register of the Cochrane Complementary Field (last searched September 2003) and the Chinese Stroke Trials Register (last searched September 2003). In addition we searched the following bibliographic databases: The Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 4, 2002), MEDLINE (1996 to December 2002), EMBASE (1980 to December 2002), CINAHL (1982 to December 2002), AMED (1985 to December 2002) and China Biological Medicine Database (CBM-disc 1979 to December 2002). We handsearched 10 Chinese journals, searched clinical trials and research databases, scanned reference lists and contacted the pharmaceutical company manufacturing Dan Shen. SELECTION CRITERIA: Randomised controlled trials or quasi-randomised controlled clinical trials comparing Dan Shen agents with placebo or open control (no placebo) in patients with acute ischaemic stroke. DATA COLLECTION AND ANALYSIS: Two reviewers independently selected trials for inclusion, assessed trial quality and extracted the data. MAIN RESULTS: Eight potentially eligible trials were identified, of which three trials (304 patients) were included. Two trials were excluded and three trials are awaiting assessment. Numbers of deaths and dependent patients at the end of follow-up of at least three months were not reported in the three included trials. Only one trial reported adverse events. Three trials measured the outcome "significant improvement in neurological deficit at the end of treatment". Compound Dan Shen agents were associated with a significant increase in the number of patients with the outcome (Peto Odds Ratio (OR) 2.72, 95% Confidence Interval (CI) 1.10 to 6.72). No deaths were reported within the first two weeks of treatment or during the whole follow-up period (21 to 28 days). The trials did not include any assessment of quality of life. REVIEWERS' CONCLUSIONS: There were too few patients and outcome events to draw reliable conclusions from the present data. The methodological qualities of all included studies were poor. Further high-quality randomised controlled trials should be performed.

Acute Disease↗

PubMed2004

Roles of nonequilibrium conduction electrons on the magnetization dynamics of ferromagnets.

The mutual dependence of spin-dependent conduction and magnetization dynamics of ferromagnets provides the key mechanisms in various spin-dependent phenomena. We compute the response of the conduction electron spins in a spatial and time varying magnetization M(r,t) in the time-dependent semiclassical transport theory. We show that the induced nonequilibrium conduction spin density in turn generates four spin torques acting on the magnetization-with each torque playing a different role in magnetization dynamics. By comparing with recent theoretical models, we find that one of these torques which has not been previously identified is crucial to consistently interpreting experimental data on domain wall motion.

Journal Article↗

PubMed2004

Mapping Ds insertions in barley using a sequence-based approach.

A transposon tagging system, based upon maize Ac/Ds elements, was developed in barley (Hordeum vulgaresubsp. vulgare). The long-term objective of this project is to identify a set of lines with Ds insertions dispersed throughout the genome as a comprehensive tool for gene discovery and reverse genetics. AcTPase and Ds-bar elements were introduced into immature embryos of Golden Promise by biolistic transformation. Subsequent transposition and segregation of Ds away from AcTPase and the original site of integration resulted in new lines, each containing a stabilized Ds element in a new location. The sequence of the genomic DNA flanking the Ds elements was obtained by inverse PCR and TAIL-PCR. Using a sequence-based mapping strategy, we determined the genome locations of the Ds insertions in 19 independent lines using primarily restriction digest-based assays of PCR-amplified single nucleotide polymorphisms and PCR-based assays of insertions or deletions. The principal strategy was to identify and map sequence polymorphisms in the regions corresponding to the flanking DNA using the Oregon Wolfe Barley mapping population. The mapping results obtained by the sequence-based approach were confirmed by RFLP analyses in four of the lines. In addition, cloned DNA sequences corresponding to the flanking DNA were used to assign map locations to Morex-derived genomic BAC library inserts, thus integrating genetic and physical maps of barley. BLAST search results indicate that the majority of the transposed Ds elements are found within predicted or known coding sequences. Transposon tagging in barley using Ac/Ds thus promises to provide a useful tool for studies on the functional genomics of the Triticeae.

Base Sequence↗

PubMed2004

Oestrogen inhibits resveratrol-induced post-translational modification of p53 and apoptosis in breast cancer cells.

Resveratrol, a naturally occurring stilbene, induced apoptosis in human breast cancer MCF-7 cells. The mechanism of this effect was dependent on mitogen-activated protein kinase (MAPK, ERK1/2) activation and was associated with serine phosphorylation and acetylation of p53. Treatment of MCF-7 cells with resveratrol in the presence of 17beta-oestradiol (E(2)) further enhanced MAPK activation, but E(2) blocked resveratrol-induced apoptosis, as measured by nucleosome ELISA and DNA fragmentation assays. E(2) inhibited resveratrol-stimulated phosphorylation of serines 15, 20 and 392 of p53 and acetylation of p53 in a concentration- and time-dependent manner. These effects of E(2) on resveratrol action were blocked by ICI 182,780 (ICI), an inhibitor of the nuclear oestrogen receptor-alpha (ER). ICI 182,780 did not block the actions of resveratrol, alone. Electrophoretic mobility studies of p53 binding to DNA and of p21 expression indicated that E(2) inhibited resveratrol-induced, p53-directed transcriptional activity. These results suggest that E(2) inhibits p53-dependent apoptosis in MCF-7 cells by interfering with post-translational modifications of p53 which are essential for p53-dependent DNA binding and consequent stimulation of apoptotic pathways. These studies provide insight into the complex pathways by which apoptosis is induced by resveratrol in E(2)-depleted and -repleted environments.

Antineoplastic Agents, Phytogenic↗

PubMed2004

Domain-wall dynamics and spin-wave excitations with spin-transfer torques.

A generalization of spin-transfer torques in ferromagnetic structures is proposed. For a spatially nonuniform magnetization, the spin torque has a form nearly identical to that in magnetic multilayers. We show that the domain-wall motion driven by the current has many unique features that do not exist in the conventional domain-wall motion driven by a magnetic field. We also demonstrate that the spin torque can generate bulk and surface spin excitations that have been seen in point-contact experiments.

Journal Article↗

PubMed2004

Phase I and pharmacokinetic study of irinotecan in combination with R115777, a farnesyl protein transferase inhibitor.

The aims of this study were to determine the maximum-tolerated dose (MTD), toxicity profile, and pharmacokinetics of irinotecan given with oral R115777 (tipifarnib), a farnesyl protein transferase inhibitor. Patients were treated with escalating doses of irinotecan with interval-modulated dosing of R115777 (continuously or on days 1-14, and repeated every 21 days). In total, 35 patients were entered onto the trial for a median duration of treatment of 43 days (range, 5-224 days). Neutropenia and thrombocytopenia were the dose-limiting toxicities; other side effects were mostly mild. The MTD was established at R115777 300 mg b.i.d. for 14 consecutive days with irinotecan 350 mg x m(-2) given every 3 weeks starting on day 1. Three patients had a partial response and 14 had stable disease. In the continuous schedule, the area under the curves of irinotecan and its active metabolite SN-38 were 20.0% (P=0.004) and 38.0% (P<0.001) increased by R115777, respectively. Intermittent dosing of R115777 at a dose of 300 mg b.i.d. for 14 days every 3 weeks is the recommended dose of R115777 in combination with the recommended single-agent irinotecan dose of 350 mg x m(-2).

Administration, Oral↗

PubMed2004

Biphasic effect of daidzein on cell growth of human colon cancer cells.

Colorectal cancer is one of the most common cancers in the world, poorly responding to available chemotherapeutic agents. To investigate whether natural molecules can inhibit colon cancer progression, we investigated a principle phytoestrogen found in soybean known as daidzein, and determined its effects on the human colon cancer cell line LoVo. LoVo cells were treated with 0.1, 1, 5, 10, 50 and 100 microM daidzein for 2, 3, 4 or 5 d. The results indicated that daidzein stimulated the growth of LoVo cells at 0.1 and 1 microM whereas at higher concentrations (10, 50 and 100 microM) cell growth was inhibited in a dose-dependent manner. Treatment of daidzein at 10, 50 and 100 microM resulted in cell cycle arrest at G0/G1 phase, DNA fragmentation and increases in caspase-3 activity. There were no changes in alkaline phosphatase activity (ALP), an indicator of cell differentiation, upon treatment with daidzein when compared to controls. These results indicate that daidzein has a biphasic effect on LoVo cell growth and its tumor suppressive effect is by means of cell cycle arrest and apoptosis but not through cell differentiation.

Alkaline Phosphatase↗

PubMed2004

New methods for molecular diagnosis and demonstration of the (CCTG)n mutation in myotonic dystrophy type 2 (DM2).

Myotonic dystrophy types 1 and 2 are autosomal dominant, multisystemic disorders with many similarities in their clinical manifestations. Myotonic dystrophy type 1 is caused by a (CTG)n expansion in the 3' untranslated region of the DMPK gene in 19q13.3 and myotonic dystrophy type 2 by a (CCTG)n expansion in intron 1 of ZNF9 in 3q21.3. However, the clinical diagnosis of myotonic dystrophy type 2 is more complex than that of myotonic dystrophy type 1, and conventional molecular genetic methods used for diagnosing myotonic dystrophy type 1 are insufficient for myotonic dystrophy type 2. Herein we describe two in situ hybridization protocols for the myotonic dystrophy type 2 mutation detection. Chromogenic in situ hybridization was used to detect both the genomic expansion and the mutant transcripts in muscle biopsy sections. Chromogenic in situ hybridization can be used in routine myotonic dystrophy type 2 diagnostics. Fluorescence in situ hybridization on extended DNA fibers was used to directly visualize the myotonic dystrophy type 2 mutation and to estimate the repeat expansion sizes.

Adult↗

PubMed2004

Association between apolipoprotein CI HpaI polymorphism and sporadic Alzheimer's disease in Chinese.

OBJECTIVE: To investigate into the relationship of apolipoprotein CI (ApoCI) polymorphism with sporadic Alzheimer's disease (AD) in Chinese. SUBJECTS AND METHODS: A total of 257 AD patients and 242 age-matched elderly individuals were genotyped for the ApoCI HpaI and apolipoprotein E (ApoE) HhaI polymorphisms. RESULTS: The ApoCI A allele was associated with AD of moderate to severe dementia when patients were divided into two subgroups according to Clinical Dementia Rating scale, and the AA genotype was strongly associated with moderate to severe AD in ApoE epsilon4 allele carriers [odds ratio (OR) = 8.19, 95% confidential interval: 1.28-52.30, after adjusting for age and gender by logistic regression analysis], although in total no significant differences of allele or genotype frequency between patients and controls were found. CONCLUSION: The present study partially confirmed the previous findings, suggesting that the ApoCI A allele might contribute to the susceptibility to moderate to severe sporadic AD in Chinese.

Aged↗

PubMed2004

Phase II study of the farnesyl transferase inhibitor R115777 in patients with sensitive relapse small-cell lung cancer.

BACKGROUND: R115777 (tipifarnib, Zarnestra) is a farnesyl transferase inhibitor that blocks the farnesylation of proteins involved in signal transduction pathways critical for cell proliferation and survival. This multicenter phase II study was conducted to determine the efficacy, tolerability and pharmacokinetics of R115777 in patients with relapsed small-cell lung cancer (SCLC). PATIENTS AND METHODS: Patients who had a partial or complete response to their initial chemotherapy regimen, followed by at least 3 months off treatment before relapse (sensitive relapse) were eligible. R115777 was administered in 3-week cycles at a dose of 400 mg orally twice daily for 14 consecutive days followed by 7 days off treatment. RESULTS: Twenty-two patients were enrolled. The median progression-free survival was 1.4 months and median overall survival was 6.8 months. Non-hematological toxicities were predominantly grade 1-2 and included nausea (64%) and fatigue (60%). Grade 3-4 granulocytopenia and thrombocytopenia occurred in 27% and 23% of patients, respectively. Febrile neutropenia was not observed. Pharmacokinetic studies demonstrated peak plasma concentrations of R115777 2.6-4.5 h after oral dosing and no significant drug accumulation. The trial was terminated because no objective responses were observed in 20 patients evaluable for response. CONCLUSIONS: R115777 showed no significant antitumor activity as a single agent in sensitive-relapse SCLC.

Adult↗

PubMed2004

Purification and characterization of a new reovirus from the Chinese mitten crab, Eriocheir sinensis.

A new reovirus was recently isolated from a freshwater crab, the Chinese mitten crab, Eriocheir sinensis, in China. The complete viral particles are 55 nm in diameter, icosahedral, non-enveloped and have a mean buoyant density of 1.39 g cm(-3) in CsCl gradient. The viral genome is composed of 12 pieces of dsRNA with an electrophoretic pattern of 3/4/2/3. This virus infects connective tissue of the gills, gut and hepatopancreas. Partial cDNA cloning and sequence analysis showed that the RNA-dependent RNA polymerase is located in the first RNA segment. From its biochemical, ultrastructural and physicochemical properties, this virus is quite different from the genus Aquareovirus (Reoviridae). It may represent a new genus of Reoviridae, different from the other crab reoviruses, P and W(2).

Amino Acid Sequence↗

PubMed2004

Haplotype block definition and its application.

We present a simple two-stage procedure to define haplotype blocks and construct a statistic to test whether a polymorphism belongs to a block. Applying this method to the data of Gabriel et al. [2002] yielded longer haplotype blocks than were originally reported with a similar average percentage of common haplotypes in blocks. Furthermore, across regions of the genome and among the four populations that were studied, we found that linkage disequilibrium between a given single nucleotide polymorphism (SNP) and the haplotype block was a monotonic function of distance. This correlation was essentially independent of the minor allele frequency of the putative causal SNP when it fell outside of the block, however it was strongly dependent on the minor allele frequency when the SNP was internal to the block. These results have direct application to the design of candidate gene or region-wide association studies.

Algorithms↗