Biomedical subjects

Yan Sun

Publications and source records attributed to Yan Sun.

At least 37 records · Page 2Linked to original sources

PubMed2006

Advanced oxidation protein products induce monocyte chemoattractant protein-1 expression via p38 mitogen-activated protein kinase activation in rat vascular smooth muscle cells.

BACKGROUND: Advanced oxidation protein products (AOPPs) are new uremic toxins reported by Witko-Sarsat in 1996, which are associated with the pathogenesis of atherosclerosis. However, the mechanisms by which AOPPs enhance atherosclerosis have not been fully understood. Monocyte chemoattractant protein-1 (MCP-1) is a chemokine which stimulates migration of monocytes and plays a critical role in the development of atherosclerosis. In this study, we investigated the effect of AOPPs on MCP-1 expression in cultured vascular smooth muscle cells (VSMCs). METHODS: VSMCs were cultured and then co-incubated with AOPP (200 micromol/L, 400 micromol/L) for different times with or without pretreatment with specific p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580. RT-PCR and Western blott were used to detect MCP-1 mRNA and protein expression at different time points after AOPP stimulation in rat smooth muscle cells. Western blot was used to detect the expression of phosphorylated p38 MAPK. RESULTS: Treatment of VSMC with AOPPs resulted in a significant increase of the expression of MCP-1 mRNA and protein in time- and dose-dependent manner, and could activated p38 MAPK. Pretreatment of VSMCs with SB203580 resulted in a dose-dependent inhibition of AOPPs-induced MCP-1 mRNA and protein expression. CONCLUSIONS: AOPPs can stimulate MCP-1 expression via p38 MAPK in VSMCs. This suggests that AOPPs might contribute to the formation of atherosclerosis through this proinflammatory effect.

Animals↗

PubMed2006

Characterization and quantification of eight water-soluble constituents in tubers of Pinellia ternata and in tea granules from the Chinese multiherb remedy Xiaochaihu-tang.

In traditional Chinese medicine, multiple herbs are usually used in combination to generate the joint actions of a multiherb remedy. The recent development of LC-hyphenated techniques enables efficient and rapid profiling of the chemical constituent in extracts from multiherb remedies. Xiaochaihu-tang is a seven-herb remedy that has attracted a great deal of attention for reported ability to treat liver dysfunction. Dried tubers of Pinellia ternata (banxia in Chinese) is one of the ingredients, but its chemical contribution to Xiaochaihu-tang remains poorly understood. In the study presented here, LC-UV-MS, LC-MS-MS, and LC-NMR were used in a complementary manner to determine the nature and content of eight water-soluble constituents of banxia and their presence in various tea granules from Xiaochaihu-tang. Among the eight chemicals identified in banxia, cytidine, adenosine, tryptophan, uridine, and adenine are reported for the first time, while tyrosine, guanosine, and phenylalanine were previously described. These chemicals are also present in all of the samples of Xiaochaihu-tang granules, and the amounts of the chemicals ingested due to a daily dose of the multiherb remedies range from 0.008 to 6.3mg.

Adenine↗

PubMed2006

Determination of the big head carp myofibrillar (Aristichthys nobilis) adenosine triphosphatase activity by ion chromatography.

A method for the determination of adenosine triphosphatase (ATPase) activity of myofibrils of big head carp by using ion chromatography was introduced. Adenosine triphosphate (ATP), adenosine diphosphate (ADP) and orthophosphate (Pi) were separated completely. Recoveries for ATP, ADP and Pi were 98+/-5%, 97+/-4% and 98+/-5%, respectively. Pi liberated from ATP during reaction was monitored by ion chromatography using the suggested method. This method was applicable to the determination of myofibrils ATPase activity for quick quality evaluation of surimi.

Adenosine Triphosphatases↗

PubMed2006

A hybrid vector for ligand-directed tumor targeting and molecular imaging.

Merging tumor targeting and molecular-genetic imaging into an integrated platform is limited by lack of strategies to enable systemic yet ligand-directed delivery and imaging of specific transgenes. Many eukaryotic viruses serve for transgene delivery but require elimination of native tropism for mammalian cells; in contrast, prokaryotic viruses can be adapted to bind to mammalian receptors but are otherwise poor vehicles. Here we introduce a system containing cis-elements from adeno-associated virus (AAV) and single-stranded bacteriophage. Our AAV/phage (AAVP) prototype targets an integrin. We show that AAVP provides superior tumor transduction over phage and that incorporation of inverted terminal repeats is associated with improved fate of the delivered transgene. Moreover, we show that the temporal dynamics and spatial heterogeneity of gene expression mediated by targeted AAVP can be monitored by positron emission tomography. This new class of targeted hybrid viral particles will enable a wide range of applications in biology and medicine.

Animals↗

PubMed2006

Distribution patterns of nitrobenzenes and polychlorinated biphenyls in water, suspended particulate matter and sediment from mid- and down-stream of the Yellow River (China).

Samples of water, suspended particulate matter (SPM) and sediment were collected from mid- and down-stream of the Yellow River. The distribution and concentration of 10 nitroaromatic compounds and polychlorinated biphenyls (PCBs) were extensively studied. The total concentration of 10 nitrobenzenes (SigmaNBs) varied from 0.269 to 9.052 microg l(-1) in water, from 2.916 to 164.4 microg kg(-1) dry weight in SPM, and from 0.954 to 14.72 microg kg(-1) dry weight in sediment. PCBs associated with the sediments, measured as the summed responses of Aroclor 1242, 1248, 1254, 1260 (in comparison to those of a standard 1:1:1:1 mixture), were found to be in the range of non-detectable to 5.98 microg kg(-1). In the samples collected, various PCB congeners showed similar distribution characteristics with congeners containing 3-5 chlorine atoms accounting for more than 96.4% of total PCB. In most of the samples, PCB concentrations occurred in the order: TetraCB > TriCB > PentaCB. Levels of SigmaNBs in the Yellow River were relatively low in comparison with values reported from other river and marine systems, and PCB levels were comparatively low. Relative to the PCBs, SigmaNBs showed significantly more difference among the various stations, presumably due to the influence of different pollution sources. No obvious correlation was observed between the pollutant concentrations and either the TOC or the grain size of the sediments.

China↗

PubMed2006

Mutation analysis of the FOXL2 gene in Chinese patients with blepharophimosis-ptosis-epicanthus inversus syndrome.

Blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) is an autosomal dominant disorder characterized by blepharophimosis, ptosis and epicanthus inversus. Based on the presence and absence of premature ovarian failure, two clinical types have been distinguished. Both types of BPES have been mapped to chromosome 3q23 and are mostly due to mutations of a forkhead transcription factor FOXL2 gene which locates at this region. We screened for FOXL2 mutations in Chinese patients with BPES. A novel mutation (g.901-930dup30) which could result in an expansion of the polyalanine tract was found in two BPES type II families and one sporadic case. In addition, a new g.952delC mutation was identified in two patients from a BPES family of undetermined type. The previously reported g.892C>T (p.Q219X) was also found in 12 patients from a large BPES family of type I. No mutations were detected in three other BPES families and three sporadic cases. So we speculate that in a fraction of the BPES patients the genetic defect may represent a change in gene dosage or a rearrangement outside the transcription unit of FOXL2.

Adult↗

PubMed2006

Oscillatory transverse electric field enhances protein resolution and capacity of size-exclusion chromatography.

Protein separations by a novel size-exclusion electrochromatography (SEEC) are presented. The present SEEC, denoted as pSEEC, was established with an oscillatory low-voltage electric field perpendicular to the mobile-phase streamline. Retention experiments with different proteins indicated that the influence of electric field strength on the partition coefficient is different for different proteins as well as for the same protein under different mobile-phase conditions. These results of protein retention led to the experimental design of protein separations with binary mixtures of BSA and immunoglobulin G (IgG), myoglobin (Myo) and lysozyme (Lys), as well as ovalbumin (Oval) and Myo. The separation results for the binary protein systems sufficiently exhibited the applicability of the pSEEC for various separations in terms of their molecular weights (MWs) as well as pIs. For example, it was possible to separate the gel-excluded proteins (BSA/IgG) as well as gel-permeable and similar-molecular-weight proteins (Myo/Lys) by the pSEEC. Moreover, in the cases of Oval/ Myo, which could be partially separated by size-exclusion chromatography, the use of the pSEEC greatly improved the resolution and the separation became possible at high sample loading. The results indicate that the pSEEC technology is promising for preparative protein separations.

Animals↗

PubMed2006

High-capacity purification of hen egg-white proteins by ion-exchange electrochromatography with an oscillatory transverse electric field.

The ion-exchange electrochromatography with an oscillatory electric field perpendicular to the mobile-phase flow driven by pressure (pIEEC) was used to separate hen egg-white (HEW) proteins. The results were compared with those of normal ion-exchange chromatography (IEC). The column was designed as three-compartment rectangular column of 2-mL with dimensions (length x width x depth) of 40 x 10 x 5 mm(3) and the electric field was applied across the direction of column width. Q Sepharose FF was packed into the central compartment as the chromatographic bed. It was confirmed that the dynamic binding capacity (DBC) of different proteins (ovotransferrin and ovalbumin) in the HEW solution increased 2.3 times when an oscillatory electric current of 30 mA at 1/20 Hz was applied in the transverse column direction. Then, the HEW proteins were separated by the pIEEC at loading amounts 2.3-fold higher than those by the IEC. When the feedstock of about one-third of the DBC was applied to the columns (i.e., 7 mL for the pIEEC and 3 mL for the IEC), similar separation efficiencies of the two chromatographic modes were achieved. Both the recovery yield and purity reached 73% to over 90%. The results indicate that the pIEEC is promising for high-capacity purification of proteins.

Animals↗

PubMed2006

Extent, relationship and prognostic significance of apoptosis and cell proliferation in synovial sarcoma.

AIMS: To analyse the extent, relationship and clinical significance of apoptosis and cell proliferation in synovial sarcoma. METHODS: Apoptosis was detected by TUNEL, and expression of Ki-67, Bcl-2, Bax and p53 was examined immunohistochemically in 72 synovial sarcomas. Their relation and correlation with clinicopathological parameters and survival rate were analysed. RESULTS: The average values of apoptosis index (AI) and Ki-67 labelling index (LI) were 0.76% and 28.30%, respectively. Both AI and Ki-67 LI in large-volume, high-grade and advanced-stage synovial sarcomas were significantly higher than those in small-volume, low-grade and early-stage ones (P<0.05 for all). And there was a linear relationship between AI and Ki-67 LI (r=0.751, P<0.001). All examined synovial sarcomas were positive for Bcl-2 and Bax, and only 20.8% cases showed expression of p53 protein. The expressions of Bcl-2, Bax and p53 were also significantly correlated with AI (P=0.005, P=0.002, P=0.037, respectively). In addition, patients with high AI (>0.76%) had poor prognosis (log-rank test; P=0.007). CONCLUSIONS: Alterations in apoptosis and cell proliferation activity might be responsible for the pathogenesis and behaviour of synovial sarcoma. Increased rate of apoptosis in synovial sarcoma was considered to be an indicator of poor prognosis. In addition, apoptosis in synovial sarcoma may be controlled by multiple apoptosis-regulating mechanisms, including the Bcl-2 family and p53 protein.

Adolescent↗

PubMed2006

Effects of acute and chronic restraint stress on visceral sensitivity and neuroendocrine hormones in rats.

OBJECTIVE: To investigate the effects of acute and chronic partial restraint stress (PRS) on visceral sensitivity to colorectal distention and the neuroendocrine response in rats. METHODS: Male Sprague-Dawley rats were used in this study. The abdominal withdrawal reflex score was assessed before stress, immediately after acute or chronic PRS, and 7 days after the first stress. The plasma levels of corticosterone (CORT) and adrenocorticotropic hormone (ACTH) were detected by radioimmunoassay at different time points. RESULTS: The abdominal withdrawal reflex scores of the rats with acute or chronic PRS were significantly higher immediately after stress than those before and 7 days after the stress (P < 0.05). The levels of CORT (25.35 +/- 6.03 ng/mL) and ACTH (312.47 +/- 50.76 pg/mL) in rats with acute PRS showed a significant elevation immediately after stress compared to rats without PRS (7.24 +/- 2.97 ng/mL, 97.00 +/- 23.33 pg/mL, P < 0.05). However, these hormones returned to the baseline value 7 days after acute PRS. The levels of CORT (20.84 +/- 2.19 ng/mL) and ACTH (200.41 +/- 78.10 pg/mL) in rats with chronic PRS were significantly higher after stress than in rats without PRS (P < 0.05), and these hormones remained elevated 7 days after chronic PRS. CONCLUSIONS: Both acute and chronic PRS induce reversible visceral hypersensitivity. Acute PRS transiently elevates the plasma levels of CORT and ACTH, whereas chronic PRS has a longer term effect.

Abdomen↗

PubMed2006

Role of 11-beta-hydroxysteroid dehydrogenase type 1 in differentiation of 3T3-L1 cells and in rats with diet-induced obesity.

AIM: To observe the roles of 11-beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) in in vitro preadipocyte differentiation and in rats with diet-induced obesity (DIO). METHODS: Protein expression of 11beta-HSD1 in the process of 3T3-L1 cell differentiation and in various tissues of the rats were detected by Western blot analysis; expression of 11beta-HSD1 mRNA and glucocorticoid receptor (GR) and other marker genes of preadipocyte differentiation were detected by using real-time PCR. RESULTS: Lipid droplets in 3T3-L1 cells accumulated and increased after stimulation. A dramatically elevated protein level of 11beta-HSD1, especially in the late stages of 3T3-L1 cell differentiation, was detected. The relative mRNA levels of 11beta-HSD1, GR and cell differentiation markers LPL, aP2, and FAS were upregulated, and Pref-1 was downregulated during the differentiation. In DIO rats, bodyweight, visceral adipose mass index and the protein expression of 11beta-HSD1 increased, especially in adipose tissue, brain and muscles. Serum insulin, triglyceride, total cholesterol and low-density lipoprotein cholesterol were found to be increased in DIO rats, but without any obvious changes in blood glucose or tumor necrosis factor-alpha levels. CONCLUSION: 11beta-HSD1 may promote preadipocyte differentiation, and may be involved in the development of obesity.

11-beta-Hydroxysteroid Dehydrogenase Type 1↗

PubMed2006

Staphylococcus aureus-induced corneal inflammation is dependent on Toll-like receptor 2 and myeloid differentiation factor 88.

Toll-like receptors (TLRs) expressed by the corneal epithelium represent a first line of host defense to microbial keratitis. The current study examined the role of TLR2, TLR4, and TLR9 and the common adaptor molecule myeloid differentiation factor 88 (MyD88) in a Staphylococcus aureus model of corneal inflammation. The corneal epithelia of C57BL/6, TLR2(-/-), TLR4(-/-), TLR9(-/-), and MyD88(-/-) mice were abraded using a trephine and epithelial brush and were exposed to heat- or UV-inactivated S. aureus clinical strain 8325-4 and other clinical isolates. Corneal thickness and haze were measured by in vivo confocal microscopy, neutrophil recruitment to the corneal stroma was quantified by immunohistochemistry, and cytokine production was measured by enzyme-linked immunosorbent assay. The exposure of corneal epithelium to S. aureus induced neutrophil recruitment to the corneal stroma and increased corneal thickness and haze in control C57BL/6 mice but not in TLR2(-/-) or MyD88(-/-) mice. The responses of TLR4(-/-) and TLR9(-/-) mice were similar to those of C57BL/6 mice. S. aureus-induced cytokine production by corneal epithelial cells and neutrophils was also significantly reduced in TLR2(-/-) mice compared with that in C57BL/6 mice. These findings indicate that S. aureus-induced corneal inflammation is mediated by TLR2 and MyD88 in resident epithelial cells and infiltrating neutrophils.

Adaptor Proteins, Signal Transducing↗

PubMed2006

Wolbachia- and Onchocerca volvulus-induced keratitis (river blindness) is dependent on myeloid differentiation factor 88.

Endosymbiotic Wolbachia bacteria that infect the filarial nematode Onchocerca volvulus were previously found to have an essential role in the pathogenesis of river blindness. The current study demonstrates that corneal inflammation induced by Wolbachia or O. volvulus antigens containing Wolbachia is completely dependent on expression of myeloid differentiation factor 88.

Adaptor Proteins, Signal Transducing↗

PubMed2006

[Meta-analysis of the association of the LRP C766T polymorphism with the risk of Alzheimer's disease].

A C-to-T polymorphism in exon 3 of the low density lipoprotein receptor-related protein 1 (LPR-1) gene has been implicated as a risk factor for Alzheimer's disease (AD). The authors performed a meta-analysis to investigate the association between the C766T polymorphism in the LPR-1 gene and the risk for AD. Nineteen references were retrieved through Medline, Cochran Library and CBM search from 1997 to 2004. Similar search strategies were applied to each of these databases. Studies which were eligible for the meta-analysis should meet the following inclusion criteria: presentation of original data and a cross-sectional design, AD as the outcome of interest, an odds ratio (or enough information to calculate it) reported to quantify the association between the frequencies of genotypes and/or alleles of LPR-1 gene C766T polymorphism and the risk for AD. All analyses were performed with Review Manager 4.2. A total of 3,560 AD patients and 3,476 control subjects were analyzed according to the random effect model because some between-study heterogeneity was found (P<0.01). The combined data statistics revealed that there was no statistical difference (test for overall effect: Z=1.74, P=0.08, OR=1.17, 95% CI: 0.98-1.39; Z=1.31, P=0.19, OR=1.11, 95% CI: 0.95-1.31) in the frequencies of allele and genotype between the AD patients and the controls. The meta-analysis showed that the LPR-1 polymorphism was not a major risk factor for AD, although a small effect of the polymorphism for AD risk could not be excluded.

Age of Onset↗

PubMed2006

[Clinical features of 89 patients with primary non-Hodgkin's lymphoma of the tonsil].

BACKGROUND & OBJECTIVE: Head and neck lymphoma develops predominantly in the tonsil. This study was to investigate the clinical features of primary non-Hodgkin's lymphoma (NHL) of the tonsil, and to explore possible ways to improve the prognosis and quality of life of the patients after treatment. METHODS: Clinical data of 89 naive patients with NHL of the tonsil, treated from May 1990 to Jan. 2003, were retrospectively reviewed. All patients were confirmed pathologically and classified according to revised European-American Lymphoid Neoplasms and World Health Organization Classification, and staged according to the Ann Arbor classification. Stage I-II patients received radiochemotherapy-predominant treatment, whereas stage III-IV patients received chemotherapy-predominant treatment. RESULTS: Of the 89 cases, 60 (67%) were diffuse large B-cell subtype, 11 (12%) were peripheral T-cell subtype, 5 (6%) were indolent lymphoma, 1 was anaplastic large T-cell lymphoma, and 1 was T lymphoblastic lymphoma; 81 (91%) were stage I-II disease. Of the 89 patients, 58 (72%) received radiochemotherapy, 19 (21%) received radiotherapy alone, 3 received chemotherapy alone, and 1 received radiochemotherapy combined with rituximab. The 5-year overall survival rate was 80%, that of stage I-II patients was 84%. Cox regression multivariate analysis showed that the survival rate was correlated to the value of international prognostic index (IPI), and whether the patient had primary refractory or relapsed disease, but was not correlated to sex, age, pathologic subtype, B symptoms, and bulky disease. CONCLUSIONS: Most patients with NHL of the tonsil are at early stages, with good prognosis. Diffuse large B-cell lymphoma is the most common pathologic subtype. Primary refractory, relapse, and IPI>1 are independent prognostic factors.

Adolescent↗

PubMed2006

[Phase I clinical trail of intravenous pegylated recombinant human granulocyte colony-stimulating factor].

BACKGROUND & OBJECTIVE: Recombinant human granulocyte colony-stimulating factor (rhG-CSF) is effective in the prophylaxis and management of chemotherapy-induced neutropenia, but requires daily administration because of its short half-life. Pegylated rhG-CSF (PEG-rhG-CSF) is a long-acting reagent that permits less frequent injection. This study was to evaluate the safety and tolerance of PEG-rhG-CSF in Chinese patients, and to explore its efficacy of enhancing absolute neutrophil count (ANC) and CD34+ cell count in peripheral blood. METHODS: Naïve non-small lung cancer or breast cancer patients with normal bone marrow function were eligible for this open-labeled, dose-escalation trial. All patients received 2 cycles of chemotherapy of identical regimen. In cycle 1, rhG-CSF (150 microg/day) was administrated in case of febrile neutropenia or grade 4 neutropenia; in cycle 2, patients received a single injection of PEG-rhG-CSF (30 microg/kg, 60 microg/kg, 100 microg/kg, or 200 microg/kg) 48 h after administration of paclitaxel and carboplatin. RESULTS: All the 16 patients enrolled (4 in each dose group) were evaluable for safety and efficacy of PEG-rhG-CSF. Main adverse events related to PEG-rhG-CSF were musculoskeletal pain or arthralgia (13/16), fatigue (10/16), dizziness (2/16), and injection-site pain (1/16). All adverse events were mild to moderate, and most of them were reversible without treatment. PEG-rhG-CSF enhanced ANC in a dose-dependent manner to some extent, and PEG-rhG-CSF at 60 microg/kg or higher doses prevented chemotherapy-induced neutropenia with sustained effect; CD34+ cells in peripheral blood were also increased. CONCLUSIONS: PEG-rhG-CSF is well tolerated, with no serious adverse event in this trial. The recommended dose of PEG-rhG-CSF for phase II trial is 100 microg/kg because of its adequate efficacy and less adverse events than those of 200 microg/kg.

Adult↗

PubMed2006

[Correlation between matrix metalloproteinases-2 and tissue inhibitor of metalloproteinase-2 expression, metastatic potential and tumor angiogenesis in synovial sarcoma and its prognostic significance].

OBJECTIVE: To study the expression of matrix metalloproteinases (MMP)-2 and tissue inhibitor of metalloproteinase (TIMP)-2 in tumor cells of synovial sarcoma and its clinical significance. METHODS: Expression of MMP-2 and TIMP-2 in tumor cells of 72 cases of synovial sarcoma was studied by immunohistochemistry. The profile was correlated with clinicopathologic parameters, microvessel density (MVD) (analyzed by CD31 immunostaining) and survival rate. RESULTS: (1) There was a statistically significant negative correlation between expression of MMP-2 and TIMP-2 (r = -0.290 and P = 0.013). (2) The proportion of high MMP-2 expression to low TIMP-2 expression in patients with tumor metastasis was significantly higher than that in patients without metastasis (P = 0.010 and 0.002 respectively). (3) MVD of patients with high MMP-2 expression was higher than that in the low MMP-2 expression group (P = 0.005). MVD of patients with high TIMP-2 expression was lower than that in the low TIMP-2 expression group (P = 0.048). (4) Low TIMP-2 expression significantly correlated with poor prognosis of patients with synovial sarcoma, by univariate and multivariate survival analysis (P = 0.002 and 0.016 respectively). CONCLUSIONS: Expression of MMP-2 and TIMP-2 correlates with metastatic potential and tumor angiogenesis in synovial sarcoma. Low TIMP-2 expression often indicates poor prognosis and unfavorable clinical outcomes.

Adolescent↗

PubMed2006

[Effects of salicylic acid on chlorophyll fluorescence and xanthophyll cycle in cucumber leaves under high temperature and strong light].

In this study, cucumber leaves were under high temperature and strong light stress after two days of spraying with 50 to approximately 400 micromol x L(-1) salicylic acid (SA) solution. The measurements showed that SA pretreatment could inhibit the decrease of intrinsic photochemical efficiency (Fv/ /Fm), quantum yield of PSII(phiPSII), maximum fluorescence value (Fm), and photochemical quenching (qP) by 16.1% to approximately 30.2%, 11.9% to approximately 33.0%, 7.2% to approximately 41.0% and 27.2% to approximately 160.8%, respectively, and promote the increase of non-photochemical quenching (NPQ) by 13.1% to approximately 62.9%, but had little effect on initial fluorescence value (Fo). SA pretreatment could also inhibit the decrease of xanthophyll cycle pool in cucumber leaves, and increase the de-epoxidation extent of xanthophyll cycle (A + Z)/(V + A + Z),which was 29.5% and 24.6% higher than control, respectively. It was suggested that SA could protect the photosynthetic apparatus of cucumber leaves under high temperature and strong light through promoting non-radiative energy dissipation.

Chlorophyll↗