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Biomedical subjects

Qiang Sun

Publications and source records attributed to Qiang Sun.

At least 55 records · Page 3Linked to original sources
PubMed2004

[The effects of culture supernatant of human GRC-1 cells transfected with PF4 cDNA on the VEGF expression and the growth of ECV304 cells].

AIM: To construct the eukaryotic expression vector pcDNA3-PF4-SS, and to detect the effects of the culture supernatant of transfected GRC-1 cells on the VEGF expression in transfected GRC-1 cells and the growth of ECV304 cells. METHODS: The eukaryotic expression vector pcDNA3-PF4-SS was constructed and identified with Bgl II/BamH I digestion. The pcDNA3-PF4-SS was transfected stably into GRC-1 cells with lipofectamine mediation. The VEGF expression in transfected GRC-1 cells was detected by immunohistochemical staining, and the effect of the culture supernatant of transfected GRC-1 cells on ECV304 cells was detected by MTT colorimetry. RESULTS: Restrictive enzyme (Bgl II/BamH I)digestion analysis showed that the recombinant expression vector pcDNA3-PF4-SS had been constructed successfully. RT-PCR detection proved that hPF4 cDNA had been transfected into GRC-1 cells. The result of immunohistochemical staining showed that the VEGF expression could be seen in the cytoplasm and on cytomembrane of GRC-1 cells transfected with pcDNA3-PF4-SS, but the expression obviously weakened as comparison with that before transfection. Cell counting and MTT colorimetry manifested that the culture supernatant of transfected GRC-1 cells could inhibit markedly growth of ECV304 cells. CONCLUSION: The eukaryotic expression vector pcDNA3-PF4-SS has been constructed successfully, and stably transfected into the GRC-1 cells. The culture supernatant of transfected GRC-1 cells has obviously inhibitory effect on the growth of ECV304 cells and the VEGF expression in the GRC-1 cells, which lays some foundation for exploring the mechanism for anti-tumor growth and developing tumor vaccine for kidney neoplasms.

Carcinoma, Renal Cell↗
PubMed2004

[Cloning and primary analysis of spt1 as a ncRNA candidate gene].

In a process of screening mouse embryonic cDNA library with suc2 signal sequence trap, a strongly positive clone named spt1 was obtained repeatedly. Analysis of spt1 shows that the inserted sequence is 697 bp containing 37 start codons (ATG) and 80 stop codons (TGA, TAG, TAA), and there is no potential open reading fame in it. Similarity search by BLAST indicates that the sequence locates in the long arm of 17th chromosome, and no known genes show significant similarity with it. Northern blot and RT-PCR give positive signal specifically in ovary tissue, the full length of spt1 is about 4. 5 approximately 5.0 kb. Yeast transformation and sequence truncation experiment suggested that spt1 could mediate the secretion of invertase. Hence, spt1 may be part of a novel ncRNA gene which is involved in protein secretion.

Animals↗
PubMed2004

[Weibull analysis and flexural strength of glass-infiltrated alumina composite machined by CAD/CAM].

PURPOSE: To explore the structural reliability of machined infiltrated ceramic made from ultrafine alumina powder for dental CAD/CAM by means of flexural strength together with Weibull analysis. METHODS: Ultrafine grain-sized alumina powder made from ammonium aluminum sulfate was sintered into one kind of porous machined ceramic block. After being infiltrated by lanthanum glass powder, a glass infiltrated alumina composite was produced. Thirty bar specimens were prepared. The flexural strength was measured with the three-point bending test. The fracture stress values were analyzed by Weibull analysis to determine the Weibull modulus values(m). The strength values at failure probabilities of 1% and 5% failure were also calculated. X ray diffraction analysis (XRD) and scanning electron microscopy (SEM) analysis were conducted. RESULTS: The mean flexural strength and standard deviation were (375.5+/-66.88) MPa coupled with Weibull modulus of 6.2. Strength values at failure probability of 1% and 5% were 191.79 MPa and 249.83 MPa, respectively. The micrograph under SEM indicated the prefabricated sintered alumina block retained a structure of continuous three-dimensional open pores, whereas the composite characterized itself as a pore-free structure after glass infiltration. XRD indicated the major crystal phase was alpha-alumina. CONCLUSIONS: The average fracture strength can not be used reliably as a design parameter for brittle all-ceramic crown materials. Compared with the average fracture strength alone, the use of flexure strength test combined with the Weibull analysis as a method of predicting survival rates from the strength data could be favorable in identifying the failure mechanisms involved in ceramic crown fracture, which would result in an improved validation of the strength data.

Aluminum Oxide↗
PubMed2004

[Raman scattering study of water up to 600 MPa at 290 K].

Raman scattering studies of the stretching band from liquid water have been conducted up to 600 MPa at 290 K. It is shown that (r1)(max) decreases with increasing pressure initially and reaches the minimum at about 200 MPa, and increases at higher pressure up to about 400 MPa, then decreases with increasing pressure up to 600 MPa. And this is also in accordance with the behavior of r(oo) under pressure. The authors conclude that, just like ice phase transition ice ( I h) --> ice(II) --> ice (V), there also probably exists water phase transition water ( I h) --> water (III) --> water (V).

Crystallization↗
PubMed2004

[Evidence of discontinuous property of water: study of infrared spectra at high temperature and high pressure].

The infrared spectra measurement for water has been conducted and investigated at the temperatures of 35-350 degrees C and the pressures of 1.7-2.7 GPa by using Hydrothermal Diamond Anvil Cell (HDAC). The result shows that the peak frequency and the full width at half height of the stretching vibration of water increases and decreases respectively with increasing pressure. It also shows that there is a discontinuousness at the pressure of 2. 1 GPa, that is, the frequency and the full width at half height of the peak have an obvious and discontinuous change from the pressures below and above 2.1 GPa, indicating that the property of water is discontinuous at high pressure. This is consistent with the discontinuous property of electrical conductivity from the previous studies for pure water and NaCl aqueous solution. Also it is consistent with the relationship between the temperature and the pressure of the dehydration of the bearing water minerals at about 2.0 GPa. It is expected that such a discontinuous property of water will play an important role on the minerals and rocks in the deep lithosphere and further detailed study needs to be done for them.

Cold Temperature↗
PubMed2004

[Raman spectroscopic studies on methanol under high pressure].

This paper studies Raman spectra of methanol atpressures from 169.2 MPa up to 713.8 MPa and at ambient temperature. The result shows that the spectral profile of stretching vibrational modes of CH and OH gradually changes and Raman shift moves to higher and lower frequency respectively with increasing pressure, which indicates that the energy of C-H bonding increases with pressure, and the influence of hydrogen bonding on O-H function group is greater than that of pressure. In addition, the relative peak area of O-H stretch band decreases with pressure, showing that the total intensity of O-H bonding is weaker compared with C-H bonding.

Hydrogen Bonding↗
PubMed2003

Vascular tissue in the stem and roots of woody plants can conduct light.

The role of vascular tissue in conducting light was analysed in 21 species of woody plants. Vessels, fibres (both xylem and phloem fibres) and tracheids in woody plants are shown to conduct light efficiently along the axial direction of both stems and roots, via their lumina (vessels) or cell walls (fibres and tracheids). Other components, such as sieve tubes and parenchyma cells, are not efficient axial light conductors. Investigation of the spectral properties of the conducted light indicated that far-red light was conducted most efficiently by vascular tissue. Light gradients in the axial direction were also investigated and revealed that conducted light leaked out of the light-conducting structures to the surrounding living tissues. These properties of the conducted light suggest a close relationship with metabolic activities mediated by phytochromes. The results therefore indicate not only that signals from the external light environment can enter the interior of stems above ground and are conducted by vascular tissue towards roots under ground, but also that the light conducted probably contributes directly to photomorphogenic activities within them.

Biological Transport↗
PubMed2003

Direct observation of key reaction intermediates on gold clusters.

Using ultraviolet photoelectron spectroscopy, we provide direct experimental evidence that di-oxygen species are stable on anionic gold dimer and tetramer clusters at room temperature. The stabilization of molecular oxygen is crucial for the high activities of the low-temperature reactions on gold catalysts.

Journal Article↗
PubMed2003

[Treatment of premenopausal patients with advanced or recurrent breast cancer by chemical ablation].

OBJECTIVE: To evaluate the clinical efficacy and safety of luteinizing hormone releasing hormone (LH-RH) analog in premenopausal patients with advanced or recurrent breast cancer. METHODS: LH-RH analog (enantone 3.75 mg/2 ml) were administered to 28 premenopausal patients with advanced recurrent breast cancer and its efficacy and side effect were observed. RESULTS: The response rate (complete response and partial response) was 42.9%, and after 8 weeks of treatment, the plasma estrogen in all patients decreased to the level of postmenopause. No major adverse events were observed. CONCLUSIONS: LH-RH analog is effective and safe for premenopausal breast cancer with low adverse reaction and its administration method is easy.

Adult↗
PubMed2003

[Diagnosis and treatment of Paget's disease of the breast: report of 33 cases].

OBJECTIVE: To study the clinical features and histologic criteria of Paget's disease of breast, and evaluate the potential prognostic factors for better appropriate treatment strategies. METHODS: Thirty-three patients treated for Paget's disease of breast were reviewed retrospectively. RESULTS: The median age of diagnosis was 57 years. Twenty-nine patients were treated by modified radical mastectomy, 4 cases by mastectomy. Twenty-three (69.7%) patients had underlying carcinoma. Twenty-six (78.8%) patients did not have a palpable breast mass, 10 of them was simple Paget's disease, eight had ductal carcinoma in situ, eight had invasive ductal carcinoma. Seven patients had a palpable breast mass, and none of them was simple Paget's disease, except one of them had ductal carcinoma in situ, six had invasive ductal carcinoma. CONCLUSIONS: Most patients with Paget's disease had associated breast carcinoma. Paget's disease of the breast with a palpable breast mass is more likely to be accompanied by an invasive ductal carcinoma and had a poor prognosis. Patients with any nipple complaints deserve a serious investigation.

Adult↗
PubMed2003

[Preservative measures for blood supply to jejunal segment in reconstruction of esophagus].

OBJECTIVE: To study the effective protective measures to ensure sufficient blood supply to the jejunal segment in reconstruction of esophagus. METHODS: According to evidence based on medicine, we analyzed retrospectively 69 patients (48 cicatricial stenosis due to chemical burn, 21 defects due to excision of esophagus cancer), whose esophagus were reconstructed with free jejunal graft(in 28 cases) and with pedicle jejunal graft (in 41 cases) from 1980 to 2001. RESULTS: All patients were followed up for 1-21 years. Of 43 patients treated before 1996, 5 complicated by anastomotic leakage, 1 by strangulated intestinal obstruction; of 26 patients treated after 1996 (6 with free jejunal graft, 20 with pedicle jejunal graft), only one case complicated by anastomotic leakage. CONCLUSION: The preservative measures for good blood supply to the jejunal segment include the following aspects: (1) complete marginal vascular arcade without tension in the mesojejunum; (2) vessel anastomosis smooth; (3) 4-finger width pathway of jejunum; (4) the stable arterial blood pressure (more than 8 kPa); (5) a single-row anastomosis; and (6) the comprehensive preoperative management.

Adolescent↗
PubMed2003

[The psychological impact of mastectomy on women with breast cancer].

OBJECTIVE: To investigate the psychological impact of mastectomy on women with breast cancer. METHODS: Questionnaires were answered by 90 patients after mastectomy for breast cancer. The data were collected and analyzed regarding the age, occupation, education, income and living place of the patients. Their psychological changes were compared and evaluated statistically using chi-square analysis. RESULTS: Mastectomy caused psychological impact on half of the patients, which included fear of cancer, feeling of body incompleteness, inconvenience in working and social communication, less sexual act and low spirit. 79 percent of the patients considered breast reconstruction unnecessary. 54 percent did not know that the breast could be reconstructed. The patient feelings differed with the age, occupation, income and living place. CONCLUSION: Mastectomy hurts patient psychological health.

Age Factors↗
PubMed2002

[Different effects of acetylcholine on the action potential and force contraction in guinea pig atrial and ventricular myocardium].

The purpose of this study was to investigate the different effects of ACh on the action potential and force contraction in guinea pig atrial and ventricular myocardium by using standard microelectrodes and force transducer. The results showed that the duration of the action potential (APD) of atrial myocardium was shortened from 208.57+/-36.05 to 101.78+/-14.41 ms (n=6, P<0.01), and the APD of the ventricular myocardium was shortened from 286.73+/-36.11 to 265.16+/-30.06 ms (n=6, P<0.01).The amplitude of the action potential (APA) of the atrial myocardium was decreased from 88.00+/-9.35 to 62.62+/-20.50 mV (n=6, P<0.01), while the APA of the ventricular myocardium did not change significantly.The force contraction of atrial myocardium was inhibited completely (n=6, P<0.01), while the force contraction of ventricular myocardium was inhibited by 37.57+/-2.58% (n=6, P<0.01). The ACh effects correlated with its concentration. The K(D) of the APD shortening effects in the atrial and ventricular myocardium were 0.275 and 0.575 micromol/L. The K(D) of the negative inotropic in the atrial and ventricular myocardium were 0.135 and 0.676 micromol/L, respectively. The corresponding data points were compared using t test between the atrial and ventricular myocardium, and the differences were significant when the ACh concentration was above 10 nmol/L. Furthermore, atropine (10 micromol/L) and CsCl (20 mmol/L) blocked the effects of 10 micromol/L ACh on the APD of ventricular myocardium, while CdCl2 (0.1 mmol/L) had no influence on these effects. In conclusion, ACh could shorten the action potential duration and inhibit the force contraction of atrial and ventricular myocardium in a concentration-dependent manner. There are differences in the effects of ACh on the atrial and ventricular myocardium. The atrial myocardium is more sensitive to ACh than the ventricular myocardium. It is probable that the muscarinic receptor and the potassium channel, but not the calcium channel, are involved in the ACh-induced shortening of the ventricular APD.

Acetylcholine↗
PubMed2002

Hospital charge exemptions for the poor in Shandong, China.

Rapid economic changes in China have produced soaring hospital charges, a breakdown of the old social health insurance system, a resulting crisis in hospital affordability and renewed interest in mechanisms for discounts or exemptions from hospital charges for the poor. Little is known, however, about how effective such systems are in practice. We studied nine public hospitals in Shandong Province that offer discount or exemption mechanisms for the poor. Methods included document review, key informant interviews, detailed review of financial records and focus group discussions. These hospitals receive little government subsidy and must support themselves almost entirely through user fees. Hospital managers saw discount mechanisms primarily as marketing tools and designed them to limit their cost. Only a small fraction of hospital services were eligible for discount, and these were usually low cost or low utilization items. Discounts were generally 10-50% for selected items with very few services exempted from charge. The total value of discounts granted was 1% or less of total hospital operating budgets. Correct identification of indigents was a major difficulty for hospitals. Only a minority of indigents received discounts, the process was sometimes arbitrary and some who received discounts were not really poor. Government policies requiring discounts for the poor were vague and not enforced. The exemption programmes studied do not provide effective protection from hospital charges for the poor. To be effective, exemption mechanisms would likely require both financing and regulation by the government as well as an accurate way to identify the poor.

China↗
PubMed2002

[Screening and detecting of proteins interaction with KyoT].

To study the function of KyoT2 in vivo, two-hybrid yeast, purification of KyoT2 protein, preparation of antibody and GST-pulldown methods were used in the experiments. 42 clones were obtained after 5 x 10(6) clones were screened by four kinds of nutrition limitation and beta-galactosidase assay, 22 clones were obtained after restriction of positive clones. Finally, 13 genes were obtained by sequence assay. Two of these were RBP-Jk and PIAS1. After they and KyoT2 changed vectors, negative two-hybrid yeast was finished. The result was positive; Using KyoT2 protein and antibody GST-pulldown of KyoT2 and RBP-Jk, KyoT2 and PIAS1 were done, the result was also positive. Therefore, KyoT2 interacted with RBP-Jk and PIAS1.

Cloning, Molecular↗
PubMed2002

[Construction and expression of a vector containing protein transduction domain and bcr/abl fusion gene].

OBJECTIVE: To construct a vector containing protein transduction domain (PTD) and bcr/abl fusion gene of chronic myelogenous leukemia and express PTD-bcr/abl fusion protein in E. Coli. METHODS: DNA fragment encoding PTD was synthesized and fused to PCR-amplified bcr/abl gene fragment, then inserted into plasmid pET-16b to get the expression vector pEPb containing PTD-bcr/abl fusion gene, which was transfected and expressed in E. Coli LB21. PTD-bcr/abl fusion protein was purified by affinity chromatography. RESULTS: 523 bp bcr/abl fusion gene was effectively amplified. The PTD-bcr/abl gene sequencing showed the same sequence as scheduled. The fusion peptide was successfully expressed in E. Coli and purified. CONCLUSION: The results may provide a new PTD-bcr/abl fusion peptide for the immunotherapy of CML.

Electrophoresis, Polyacrylamide Gel↗
PubMed2002

[Bio-remediation techniques of crude oil contaminated soils].

The bioremediation of soils contaminated by different types of petroleum were carried out with composting process in a prepared bed. By the measures of nutrient- and microbiological agent addition, and moisture- and pH control, an ideal environment for microbes were obtained. When total petroleum hydrocarbons, which consist of thin oil, high condensation oil, special viscous oil, and viscous oil, were in the range of 25.8-77.2 g.kg-1 dry soil, the petroleum removal rate could reach 38.37-56.74% by 2 months operation. The contents of aromatic hydrocarbon, asphaltum and resin were important factors controlling the degradation of petroleum. 6 fungi, 6 bacteria and 1 actinomyces were found to be the dominant strains for petroleum degradation. The results could provide theoretical bases for remediation of soil contaminated by petroleum.

Bacteria↗