PubMed Health⌕ Search

Biomedical subjects

Yan Sun

Publications and source records attributed to Yan Sun.

At least 55 records · Page 3Linked to original sources
PubMed2006

[Cloning and characterization of two novel alternatively spliced transcripts of ZNF268].

ZNF268 gene encodes a typical KRAB-containing zinc finger protein, which has an amino-terminal KRAB domain and 24 carboxyl-terminal C2H2 zinc finger motifs. There is evidence that ZNF268 is expressed in human early embryos, and that it played a role in the development of human fetal liver. In this study, we use immunohistochemistry to show that ZNF268 was also expressed in hematopoietic stem cells in 3-5 week-old human embryos. ZNF268 expression was also detected in the blood cells from 7 healthy adult donors by RT-PCR. Furthermore, 4 alternative transcripts were detected in the 7 samples. By cloning and sequencing, two novel transcripts, ZNF268c and ZNF268d were identified. We predict that there is association between ZNF268 and development of hematopoietic cells.

Alternative Splicing↗
PubMed2006

[The study of 11 cases of chordoma in the skull base or neck].

OBJECTIVE: To study the clinical manifestation, histopathological types, radiological characteristics, surgical methods and the prospective efficacy of chordoma in the skull base and neck. METHOD: Analyzed the characteristics about eleven patients with chordoma in the skull base or neck that we had treated in our department from 1985 to 2003 and introduced a case of a huge chordoma in the neck. All of the patients were treated by surgery. RESULT: The clinical manifestations of chordoma in the neck or skull base were complex. The first symptoms included the mass in the neck, rhinocleisis, visuognosis fall, tinnitus, hearing loss, and damages of brain nerves. Eight cases were the typical chordoma and the other three were the cartilaginiform chordoma. The dilatant image of parenchyma was the feature in CT scan and the images often had clear confines. The cervical vertebra and the skull base were damaged in the most of the cases. Four patients (4/11) recrudesced in two years after the surgery, and eight of eleven were living more than five years after the surgery. CONCLUSION: The clinical manifestations of chordoma in the neck or skull base were complex. The cervical vertebra and the skull base were often damaged in the most of the cases. Surgery is an effective method on chordoma. The surgery path should be selected according

Adult↗
PubMed2006

[Association of the responsiveness of advanced non-small cell lung cancer to platinum-based chemotherapy with p53 and p73 polymorphisms].

OBJECTIVE: It has been proposed that genetic polymorphisms in apoptosis-related genes might be associated with sensitivity of cancer cells to platinum-based chemotherapy. This study examined the relationship between p53 and p73 genetic polymorphisms and the response to platinum-based chemotherapy in patients with advanced non-small cell lung cancer (NSCLC). METHODS: A total of 165 patients with advanced NSCLC treated with platinum-based chemotherapy were genotyped for the p53 codon 72 Pro-->Arg and p73 exon 2 G4C14-->A4T14 polymorphisms using PCR-RFLP and ARMS-PCR assays. Clinical response to the chemotherapy was obtained after 2 to 3 cycles. The adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using unconditional logistic regression model. All statistical tests were two-sided. RESULTS: The p53 Pro allele carriers had higher response rate than non-carriers (OR = 2.46; 95% CI = 1.11 - 5.45). A higher response rate was also observed for the p73 G4C14/A4T14 or A4T14/A4T14 genotype, compared with the G4C14/G4C14 genotype (OR = 2.22; 95% CI = 1.14 - 4.30). When these two polymorphisms were combined to be analyzed, it was found that the response rate in those carrying the wild-type genotypes at both genes was only 7.7%, whereas the response rates in patients carrying 1, 2, or more than 2 variant alleles of p53 and p73 were 34.8%, 42.2% and 40.7%, respectively. CONCLUSION: Those results suggest that p53 and p73 polymorphisms may be associated with clinical responsiveness to platinum-based chemotherapy in advanced NSCLC.

Adult↗
PubMed2006

[Randomized phase II trial on escalated doses of Rh-endostatin (YH-16) for advanced non-small cell lung cancer].

OBJECTIVE: To investigate the response rate (RR), time to tumor progression (TTP), quality of life (QOL) and adverse reaction in the treatment of pretreated advanced non-small cell lung cancer (NSCLC) using escalated doses of rh-endostatin (YH-16), and to determine the optimal dose for clinical application. METHODS: In this phase II randomized, controlled, multicenter trial, the patients were randomly divided into two groups to receive daily 3 hours intravenous infusion of either 7.5 mg x m(-2) or 15 mg/m(2) YH-16 for 28 days. RESULTS: Totally, 68 patients were entered and 60 patients were evaluable. There were no differences in RR (3.0% in both groups, P > 0.05), median TTP (ITT: 60 days versus 71 days, P > 0.05), QOL and incidence rate of adverse reactions (48.6% versus 38.7%, P > 0.05). No significant unexpected adverse events were observed. CONCLUSION: Rh-endostatin may have anti-tumor activity with high clinical benefit rate and is well tolerated in pretreated advanced NSCLC patients. The dose of 7.5 mg x (m(2))(-1) x d(-1) is clinically recommended.

Adolescent↗
PubMed2006

[XRCC1 and XPD genetic polymorphisms predict clinical responses to platinum-based chemotherapy in advanced non-small cell lung cancer].

OBJECTIVE: DNA repair system plays an important role in tumor sensitivity to platinum-based chemotherapy. The purpose of this study was to examine the association between polymorphisms in XRCC1 and XPD, which are involved in DNA repair, and clinical responses to platinum-based chemotherapy in advanced non-small cell lung cancer (NSCLC). METHODS: XRCC1 Arg194Trp and XPD Lys751Gln were genotyped by PCR-RFLP method in 200 patients with advanced NSCLC who received platinum-based chemotherapy. Unconditional logistic regression model was used to analyze the association between genetic polymorphisms and clinical responses. RESULTS: The overall response rate (CR + PR) was 36.0%, including 1 CR, 72 PR, 94 SD and 34 PD. The XRCC1 194Trp allele carriers had higher response rate than the subjects with the Arg/Arg genotype (adjusted OR, 2.48; 95% CI, 1.36 - 4.51, P = 0.003). However, the XPD Lys751Gln polymorphism was not found to be associated with the platinum-based chemotherapy. These two genetic polymorphisms may have some interaction in the drug sensitivity, the P value for the trend was significant (P = 0.004). CONCLUSION: Those results suggest that the XRCC1 Arg194Trp and XPD Lys751Gln genetic polymorphisms may be associated with clinical responses to platinum-based chemotherapy in advanced non-small cell lung cancer.

Adult↗
PubMed2006

[Clinical features and prognosis in breast cancer patients over 70 years of age].

OBJECTIVE: To investigate the clinical characteristics and prognostic factors in breast cancer patients over 70 years of age. METHODS: From 1980 to 2003, 280 female breast cancer patients over 70 years old were treated and the data were retrospectively reviewed. The clinical features including age, comorbidity, initial symptom, tumor size and location, pathological type, lymph node status, hormonal receptor status, treatment approaches and overall survival were analyzed. RESULTS: These 280 patients accounted for 2.9% of all breast cancer patients registered in our institution during the same period. Presentation of breast lump as initial symptom accounted for 92.5% of the patients. The median time from the presentation of initial symptom to initial diagnosis was 4 months. Major pathological type was invasive ductal carcinoma (74.3%). Estrogen or progesterone receptor was found to be positive in 72.9% by immunohistochemical staining. 165 patients (58.9%) had comorbidity such as coronary heart disease, hypertension, diabetes, etc. 256 patients underwent surgery consisting of 162 modified mastectomies, 46 mastectomies, 38 lumpectomies, 7 lumpectomies plus lymph node dissection, 2 lymph node resection and 1 with unavailable surgery record. The cumulative 5- and 10-year overall survival was 69.9% and 40.6%, respectively. Factors affecting the prognosis were tumor size, lymph node status, pathological stage, vascular invasion and endocrine therapy by univariate analysis. The lymph node status and vascular invasion were found to be two independent prognostic factors affecting significantly the prognosis by multivariate analysis. CONCLUSION: Female breast cancer patients over 70 years of age exhibit distinctive clinical and pathological characteristics. Surgery and endocrine therapy are important to achieve good clinical outcome. Lymph node status and vascular invasion are two independent prognostic factors.

Aged↗
PubMed2006

[Docetaxel in the treatment of advanced breast cancer ].

OBJECTIVE: To evaluate the efficacy, toxicity and safety of an new domestic docetaxel in the treatment of pretreated advanced breast cancer. METHODS: Fourty-four breast cancer patients who had failed in first-line chemotherapy were included in this trial. They received docetaxel as the second-line chemotherapy. Docetaxel was administered alone at a dose of 70 mg/m2 every 3 weeks. The use of granulocyte colony-stimulating factor to prevent granulocytopenia was not permitted. The response rate and toxicity were evaluated by World Health Organization toxicity scale and performance status by Karnofsky scale. RESULTS: Of the 41 evaluable patients, 4 achieved complete response and 14 partial remission, with a response rate and clinical benefit rate of 43.9% and 85.4%, respectively. Grade 3 or grade 4 neutropenia developed in 42.9%, alopecia in 7.1% and vomiting in 4.8% of these patients. Fluid retention was not observed in this series. CONCLUSION: Three-week administration of docetaxel alone at a dose of 70 mg/m2 is effective and tolerable. It provides an alternative for the pretreated advanced breast cancer patients.

Adolescent↗
PubMed2006

[Investigation and clinical significance of the micrometastasis of prelaryngeal lymph nodes in the patients with glottic carcinoma].

OBJECTIVE: To investigate the clinical significance of the micrometastasis of prelaryngeal lymph nodes in the patients with glottic carcinoma. METHOD: In prelaryngeal lymph nodes from 26 patients with glottic carcinoma, cytokeratin 19 (CK19) mRNA was detected with reverse transcription polymerase chain reaction (RT-PCR), comparing with the routine histopathologic methods (HE staining). RESULT: The positive expression of CK19 mRNA in prelaryngeal lymph nodes was detected in 8 patients (30.77%). While there was no positive finding by routine methods. The difference was significant (P < 0.05). In 8 cases with stage I glottic carcinoma, no micrometastasis in the prelaryngeal lymph node was found, and in 18 cases with stage II - VA glottic carcinoma, micrometastasis was found in 8 cases (44.44%) (P < 0.05). CONCLUSION: The detection of prelaryngeal lymph nodes micrometastasis with RT-PCR is more sensitive than with the routine histopathologic methods. The study of micrometastasis of prelaryngeal lymph nodes may provide information for the clinical management of the patients with glottic carcinoma.

Aged↗
PubMed2006

[Effect analysis of surgery for treating abnormal styloid process].

OBJECTIVE: To analyze the relationship between pharyngeal paraesthesia and abnormal styloid process, and to evaluate the surgery outcome. METHODS: One hundred and four patients with styloid process abnormality, especially those with pharyngeal paraesthesia were studied preoperatively and postoperatively. RESULTS: Among 104 patients who complained about foreign body sensation of the pharynx and a sore throat, after partial removal of styloid process, 71.2% (74/104) cured (symptoms disappeared), 12.5% (13/104) improved, while 16.3% (17/104) had no improvement. The responding rate was 83.7% (87/104). CONCLUSIONS: Not all abnormality of styloid process subjects would have pharyngeal paraesthesia, so for this kind of cases a more comprehensive analysis is necessary. Surgery via mouth is preferable.

Adult↗
PubMed2005

Methane sorption in ordered mesoporous silica SBA-15 in the presence of water.

Methane or natural gas is a practical alternative fuel of vehicles. To develop more efficient technology of on-board storage, a possibility of using SBA-15 as the methane carrier is tested. An ordered mesoporous silica molecular sieve SBA-15 is synthesized aimed at collecting the data of methane sorption in the presence of water. The synthesized material is examined with SEM, TEM, and XRD analyses, and the hexagonal channel structure is confirmed. Its textual parameters are evaluated on the basis of the adsorption data for nitrogen at 77 K, and it gives the results of 802 m2/g for the specific surface area, 1.31 cm3/g for the pore volume, a narrow pore size distribution centered at 7.7 nm, and 4 nm for the width of the partition wall. Methane sorption isotherms on SBA-15 are collected with a volumetric method for samples of different contents of water, and the enhancement of the sorption capacity due to the presence of water is observed. A discussion on the mechanism of the sorption enhancement is presented.

Journal Article↗
PubMed2005

A novel superporous agarose medium for high-speed protein chromatography.

A novel superporous agarose (SA) bead characterized by the presence of wide pores has been fabricated by water-in-oil emulsification using solid granules of calcium carbonate as porogenic agent. After cross-linking, the solid granules were removed by dissolving them in hydrochloric acid. Then, the gel was modified with diethylaminoethyl groups to create an anion exchanger, SA-DEAE, for protein adsorption. A homogeneous agarose (HA) bead was also produced and modified with DEAE for comparison. It was found that the porosity of SA-DEAE was about 6% larger than that of HA-DEAE. Moreover, both optical micrographs and confocal laser scanning microscopy (CLSM) of the ion exchangers with adsorbed fluorescein isothiocyanate (FITC) labeled IgG revealed the superporous structure of the SA medium. In addition, the SA-DEAE column had lower backpressure than the HA-DEAE column, confirming the convective flow of mobile phase through the wide pores. Due to the presence of the wide pores, more channels were available for protein transport and, furthermore, more diffusive pores in the agarose network were accessible for the protein approach from different directions. This led to 40% higher protein capacity and two times higher effective pore diffusivity in the SA-DEAE than in HA-DEAE. Moreover, an increase of the efficiency of the SA-DEAE column until a flow rate of 5 cm/min and the independency of the column efficiency at flow rates from 5 to 17.8 cm/min was found, indicating that intraparticle mass transfer was intensified by convective flow at elevated flow rates. Therefore, the chromatographic resolution of IgG and BSA was little affected up to a flow rate of 17.8 cm/min. The results indicate that the SA medium is favorable for high-speed protein chromatography.

Chromatography, Agarose↗
PubMed2005

Effect of hexanol on the reversed micelles of Span 85 modified with Cibacron Blue F-3GA for protein solubilization.

Sorbitan trioleate (Span 85) modified with Cibacron Blue F-3GA (CB) was used as an affinity surfactant (CB-Span 85) to form affinity-based reversed micelles in n-hexane. It was found that the addition of hexanol to the reversed micellar system resulted in a significant increase in water content and hydrodynamic radius of the affinity-based reversed micelles. Moreover, the reversed micelles with hexanol revealed broader aggregation number distribution and larger average aggregation number than the reversed micelles without hexanol addition. This is considered to be due to the decreases in the micellar curvature and rigidity of the micellar interfacial layer and the increase in the micellar interfacial fluidity. Consequently, the solubilization capacity of lysozyme increased about 70% in the reversed micellar solution with 3 vol% hexanol. On the other hand, the capacity of BSA was only 30% increased under the same conditions due to its larger molecular size than lysozyme. Kinetic analysis revealed that the increase in the micellar interfacial fluidity in the presence of hexanol resulted in faster release of lysozyme from the micelles, thus leading to an increase of the overall volumetric mass transfer coefficient in the back extraction.

Hexanols↗
PubMed2005

Expression pattern of growth/differentiation factor 3 in human and murine cerebral cortex, hippocampus as well as cerebellum.

Growth/differentiation factor 3 is a member of GDF/BMP subfamily of the TGF-beta superfamily, which has been reported to be implicated in testis carcinoma and deposition of adipose tissue. Interestingly, present work indicated that GDF3/Gdf3 genes were expressed in cerebral cortex, hippocampus as well as in cerebellum, as revealed by RT-PCR, in situ hybridization and immunostaining. Results of RT-PCR in 10 human tissues and 12 rat tissues indicated that GDF3/Gdf3 genes were abundantly transcribed in both human and murine brain, including cerebral cortex, hippocampus and cerebellum. In situ hybridization and immunohistochemistry results revealed that in cerebral cortex, GDF3 was evenly distributed. In hippocampus, it was expressed in most of the neurons in CA2 and DG region, especially only in a restricted number of neurons in the regions of CA1 and CA3 and in Purkinje cells in cerebellum. Present data suggested that GDF3 might play important roles in the central nervous system (CNS), especially in cerebral cortex, hippocampus and cerebellum, and it shed new light on further research of GDF3 in the central nervous system.

Animals↗
PubMed2005

Analysis of mass transport models for protein adsorption to cation exchanger by visualization with confocal laser scanning microscopy.

The mass transfer of bovine serum albumin (BSA) to a cation exchanger, SP Sepharose FF, has been studied by finite batch adsorption experiments. The uptake curve was simulated with three mass transport models (i.e., effective pore diffusion model, surface diffusion model and Maxwell-Stefan model) incorporating the particle size distribution of the adsorbent particles. All the three models can simulate the uptake curves reasonably well. However, how well these models could simulate the real concentration profile within the adsorbent particle cannot be verified by the fitness of the models to the uptake curve. Thus, confocal laser scanning microscopy (CLSM) was used to visualize protein uptake to the porous adsorbent particles during the batch experiments. Using a fluorescent dye-labeled bovine serum albumin (BSA) for the dynamic adsorption experiments, the radial concentration profiles of the labeled BSA molecules into individual adsorbent particles at different times were obtained from the CLSM images. The protein distribution profiles within various particle diameters at different time were compared with the radial protein distributions predicted from the models. It reveals that surface diffusion model describes the intraparticle protein concentration profiles better than the other two models.

Adsorption↗
PubMed2005

Characterization of reversed micelles of Cibacron Blue F-3GA modified Span 85 for protein solubilization.

The nonionic surfactant of sorbitan trioleate (Span 85) was modified with Cibacron Blue F-3GA (CB) as an affinity surfactant (CB-Span 85) to form affinity-based reversed micelles in n-hexane. The reversed micelles formed by the mixture of Span 85 and CB-Span 85 conjugate were extensively characterized in water content, hydrodynamic radius, and aggregation number. The results show that the water content and hydrodynamic radius of the reversed micelles were significantly increased by the introduction of CB ligands (CB-Span 85 conjugate), and the reversed micelles with CB-Span 85 conjugate had a wider aggregation number distribution than the Span 85 reversed micelles. Using lysozyme as a model protein, protein solubilization by the reversed micelles was investigated. Lysozyme solubilization increased significantly with the coupled CB concentration, indicating that the extraction was based upon the affinity interactions between lysozyme molecules and the CB ligand. High solubilization of lysozyme was obtained by the affinity-based reversed micelles of 62.7 mmol/L Span 85 with coupled CB higher than 0.25 mmol/L. Lysozyme recovery was carried out using a stripping solution of high ionic strength. The recovered lysozyme exhibited an activity equivalent to the native lysozyme and its secondary structure was also unchanged. The results indicate that the reversed micellar system would find potential application in protein separation.

Hexanes↗
PubMed2005

Characteristic wave detection in ECG signal using morphological transform.

BACKGROUND: Detection of characteristic waves, such as QRS complex, P wave and T wave, is one of the essential tasks in the cardiovascular arrhythmia recognition from Electrocardiogram (ECG). METHODS: A multiscale morphological derivative (MMD) transform-based singularity detector, is developed for the detection of fiducial points in ECG signal, where these points are related to the characteristic waves such as the QRS complex, P wave and T wave. The MMD detector is constructed by substituting the conventional derivative with a multiscale morphological derivative. RESULTS: We demonstrated through experiments that the Q wave, R peak, S wave, the onsets and offsets of the P wave and T wave could be reliably detected in the multiscale space by the MMD detector. Compared with the results obtained via with wavelet transform-based and adaptive thresholding-based techniques, an overall better performance by the MMD method was observed. CONCLUSION: The developed MMD method exhibits good potentials for automated ECG signal analysis and cardiovascular arrhythmia recognition.

Algorithms↗
PubMed2005

Hydrogen and methane sorption in dry and water-loaded multiwall carbon nanotubes.

Both H2 and CH4 are clean energy sources. Adsorption was considered a measure to enhance their storage, and many efforts have been dedicated to creating novel materials including carbon nanotubes as efficient carriers for them. In order to understand the uptake mechanism and the viability of practical application, eight adsorption isotherms of H2 on a sample of multiwall carbon nanotubes were collected. The heat of adsorption was determined and an isotherm model was presented. Isotherms of CH4 on the same sample were also collected. While the adsorption on dry samples behaves similarly to that of H2, the sorption behavior of CH4 in the water-loaded sample is quite different and five times higher uptake capacity was observed in the wet sample due to the formation of methane hydrates. However, carbon nanotubes are unlikely to be used as an energy carrier due to its limited surface area and pore volume.

Adsorption↗