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Biomedical subjects

Yan Sun

Publications and source records attributed to Yan Sun.

At least 145 records · Page 8Linked to original sources
PubMed2004

[Obstructive sleep apnea syndrome and hypothyroidism (a report of three cases)].

OBJECTIVE: To explore the relationship between obstructive sleep apnea syndrome (OSAS) and hypothyroidism, and to discuss the management experience. METHOD: Three cases of severity OSAS with hypothyroidism were reported and relevant literatures were reviewed. One patient underwent continuous positive airway pressure (CPAP), one patient was performed uvulopalatopharyngoplasty(UPPP), and one case is in follow-up now. RESULT: Thyroxine replacement therapy was effective in improving symptoms and nocturnal sleep apnea. CONCLUSION: Hypothyroidism probably plays a significant role in the pathogenesis of obstructive sleep apnea, the satisfactory results would be obtained by thyroxine replacement therapy, CPAP or surgical treatment can be used as adjuvant therapy in patients with this disease.

Humans↗
PubMed2004

[Clinical outcomes of women with transfusion-associated hepatitis C after 10-15 years follow-up].

BACKGROUND: To investigate natural history of hepatitis C virus (HCV) infection and related factors in China. METHODS: Totally 41 women infected with HCV 10-15 years ago were evaluated in this study. Their clinical manifestations were recorded and sera tested for alamine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyltransferase (gamma-GT), alkaline phosphatase (ALP), total bilirubin (TBIL), direct bilirubin (DBIL), total protein (TP), albumin (ALB), and alpha-fetoprotein (alpha-FP), as well as virus markers. The B-type ultrasound examination was performed on the liver, gall bladder, spleen and pancreas. For virus markers, HCV RNA was detected with fluorogenic-quantitative polymerase-chain-reaction, HBsAg and anti-HCV antibody, with enzyme-linked immunosorbent assay (ELISA). RESULTS: Ten to 15 years after infection, the infection was cleared spontaneously in 8 cases (19.51%); 73%(30/41) cases had signs at present, 32% (13/41) cases had mild ALT and/or AST elevation. On ultrasound examination, 83%(34/41) had mild degree 17%(7/41) moderate degree changes of the viral hepatitis. CONCLUSION: Women with HCV infection for 13 +/- 1 (10-15) years after transfusion had slight hepatic inflammation. A part of them had cleared the virus spontaneously.

Adult↗
PubMed2004

Association between cholesteryl ester transfer protein gene polymorphisms and variations in lipid levels in patients with coronary heart disease.

BACKGROUND: The Taq/B, Msp/ and I405V polymorphisms of cholesteryl ester transfer protein (CETP), an important regulatory factor of lipid metabolism, have been attracted much more attention by the researchers. In this study, we investigated the associations between these 3 polymorphisms of CETP gene and variations in plasma lipid and lipoprotein levels in patients with coronary heart disease (CHD). METHODS: Genomic DNA was extracted from leukocytes of 203 CHD patients and 100 control subjects using the salting out method. Genotyping of the CETP gene was performed using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) techniques. Statistical analysis was conducted using the SPSS 10.0 software package. RESULTS: The distribution of allele and genotype frequencies of the Taq/B, MspI, and I405V polymorphisms was similar in the CHD patient group and the control group. The B1B1 genotype of the Taq/B polymorphism was associated with significantly higher TC (P=0.039) and LDL-C (P=0.044) levels than the B2B2 genotype in CHD patients, and with significantly higher LDL-C (P=0.034) levels than the B2B2 genotype in controls. Homozygotes of the I405V polymorphism exhibited significantly higher HDL-C levels than VV homozygotes among control subjects (P=0.023). In male CHD patients with unambiguously assigned haplotypes, B2-M2-V/B2-M2-I patients demonstrated significantly higher HDL-C concentrations than B1-M2-V/B1-M2-I (P=0.023) and B1-M2-V/B1-M2-V patients (P=0.047). CONCLUSIONS: Genetic variations in the CETP gene may account for a significant proportion of the differences in plasma lipid and lipoprotein concentrations among the general population. The B1B1 genotype of the Taq/B polymorphism is probably a genetic risk factor for CHD in the study population.

Adult↗
PubMed2004

Genetic analysis of rice varietal diversity for rice blast control.

Two Indica hybrid rice of Shanyou63 (A) and Shanyou22 (B), two glutinous landraces of Huanghenuo (C) and Zinuo (D) and three improved Japonica rice of Hexi41 (E), Chujing12 (F) and 8126 (G) were selected and their genetic resistance relationship was estimated using resistance gene analogue (RGA). The results showed that there were similar genetic relationships between hybrid varieties at the genetic similarity (GS) of 0.86,and among improved Japonica varieties at the GS of 0.84, while highly genetic diversifications between traditional varieties, Indica and Japonica varieties, traditional and modern variety ( GS:0.45). The results also showed that clustering analysis based on RGA data were generally corresponded to known pedigrees and blast field resistances of the varieties. Based on varietal differences in RGA data and agronomic traits, plot experiments of five mixed-planting combinations of A/C, A/D, B/C, B/D and A/B and two combinations of E/C and E/F/G were conducted in Jianshui and Shiping counties ( Indica rice growing region) and Luxi County (warm Japonica region) in Yunnan Province in past two years, respectively. The results demonstrated that rice blast management was more effective in five mixed-planting combinations of varieties with different genetic backgrounds (GS: 0.45-0.77) than in two combinations with similar genetic relationships (GS: 0.84-0.90), compared with their monocultures. It is evident for the highly susceptible landraces in mixed-planting to achieve disease control, with significant decreases both in incidence and severity. The blast control efficiencies of landraces in different mixture combinations reached to 54.47%-92.18%. The control efficiencies of improved varieties varied from 15.12% to 25.54% in mixture combinations with closed genetic relationship. In addition,the total yield of 5 varietal combinations with distant genetic relationship increased 539.0-904.0 kg/ha in the mixed-planting plots, at increase rates of 5.6%-10.2%. Mixed rice varieties with similar genetic background did not achieve significant yield increase. Otherwise, the yield of E/F/G decreased 2.7%-4.0% compared with pure stand. The results can provide scientific basis of varietal combinations in diversification experiments for blast control.

Genetic Variation↗
PubMed2004

ZNF268, a novel kruppel-like zinc finger protein, is implicated in early human liver development.

The advancement in gene knockout and transgenesis have brought about enormous improvement in our understanding of mouse embryogenesis in the past decade or so. On the other hand, relatively little is known about human embryogenesis due largely to the lack of easy access to human embryos and tissues for biomedical studies. We have previously isolated a novel zinc finger gene, ZNF268, from a 3-week-old human embryo cDNA library in an effort to identify genes important for human embryonic development. To investigate the potential involvement of ZNF268 in human embryogenesis, we report here the spatial and temporal regulation of its expression during development. Northern blot and Western blot analyses revealed that ZNF268 is expressed in early embryos, predominantly, if not exclusively, in fetal liver with little detectable expression in other fetal organs. Interestingly, unlike most zinc finger proteins, ZNF268 protein was found to be localized mainly in the cytoplasm of embryonic hepatocytes. This subcellular localization was substantiated by the localization of EGFP-ZNF268 fusion protein overexpressed in the transfected COS7 cells. These results suggest that ZNF268 plays a role in early human liver development most likely by functioning through a cytoplasmic mechanism.

Antibodies↗
PubMed2004

[Construction of recombinant ZNF230/GFP fused plasmids and their expression and cellular localization].

To use green fluorescent protein as a marker to study the localization of the fusion protein, the mutant full length cDNAs of human ZNF230 and mouse znf230 with their stop codon TGA changed to TGG were obtained by PCR amplification, and then cloned into pGEM-Teasy vector. After the double enzyme cutting, the mutated human and mouse ZNF230(znf230) were inserted into mammalian expression plasmid pEGFP-N1. Thus we constructed the plasmid with fusion gene of ZNF230 and green fluorescent protein(GFP). Then the Cos cell was transfected with the fused gene by liposome. Fluorescence microscopy showed that green fluorescence protein expressed over the whole cell when transfected with vector pEGFP-N1. While after the transfection with pEGFP-ZNF230, the fluorescence located mainly on the nuclei of the cells. We demonstrated that the transfected Cos cell line can express human ZNF230 and mouse znf230 with high efficiency. When transfected with the constructed recombinant pEGFP-ZNF230 vector, the ZNF230 protein localizes mainly on the nucleus.

Animals↗
PubMed2004

[Determination of sennosides and degraded products in the process of sennoside metabolism by HPLC].

A method for the separation and determination of sennosides A and B and the main composition (sennidins A and B) in degraded products of sennosides by linear gradient high performance liquid chromatography has been developed. Separation conditions were as follows: column, a Spherisorb C18 column (250 mm x 4.6 mm i.d., 10 microm); column temperature, 40 degrees C; detection wavelength, 360 nm; mobile phase A, 1.25% acetic acid aqueous solution; mobile phase B, methanol; linear gradient, 100% A --> (20 min) 100% B. The method is effective, quick, accurate and reproducible. The satisfactory results show that this new method has certain practical values as an approach of real-time analysis in the process of sennoside metabolism.

Anthraquinones↗
PubMed2004

[Phase II study of paclitaxel and cisplatin for advanced squamous-cell carcinoma of esophagus].

OBJECTIVE: Paclitaxel was used in a phase II trial in combination with cisplatin for esophageal cancer. The anti-tumor response, toxicity and survival of the treated patients were evaluated. METHODS: Thirty patients with advanced, unresectable, or complicated with metastasis were allotted, twenty-seven patients had no prior chemotherapy while 3 patients had received adjuvant chemotherapy. Patients were given paclitaxel 175 mg/m(2) by 3-hour infusion on D1, and cisplatin 40 mg/m(2) daily on D2 and D3. Granulocyte colony-stimulating factor (G-CSF) was not routinely administered unless the patient had neutropenia. Treatment was recycled every 21 days. RESULTS: Thirty patients (male/female, 28/2; median age 58) completed a median of 3 cycles and 27 patients were evaluable for response. Major objective responses were observed in 16 patients (59.3%; 95% confidence interval, 38.9% to 75.5%), including 5 complete responses (18.5%) and 11 partial responses (40.7%). The median time to tumor progression was 5.0 months (range, 1 to 23 months). The median actuarial survival was 9.7 months (range, 1 to 23 months). Twenty-eight patients were assessable for toxicity. The most common nonhematologic toxicity was alopecia. Grade 3 to 4 neutropenia was observed in 17.9% of the patients. Toxicity was manageable with dose attenuation and G-CSF support. CONCLUSION: The combination of paclitaxel and cisplatin can be considered as a main regimen in the treatment of advanced esophageal cancer.

Adult↗
PubMed2004

[Clinical characteristic and treatment of laryngeal scleroma].

OBJECTIVE: To study the clinical manifestation and treatment of the laryngeal scleroma METHODS: Forty-three patients with laryngeal scleroma, from May, 1981 to December, 2002, with pathological diagnosed were reviewed retrospectively. The clinical features and the treatment methods of these patients were analysed. RESULTS: All 43 cases had hoarseness and 19 of them manifested dyspnea. In the larynx, the main scleromatous lesions were classified as atrophic stage in 2 cases, as granulomatous in 35 cases and as scarring in 6 cases. The preponderance lesions were located in the glottis in 13 cases, in the subglottis in 1 case, in both supraglottis and glottis in 18 cases, in both glottis and subglottis in 8 cases, and in all the three regions of the larynx in 3 cases. Twenty-four patients were treated with antibiotics, seven patients with surgery and two patients with radiotherapy. Eighteen of 24 patients who were treated with antibiotics were cured, and two of the recurrent patients were cured with a further period of antibiotics therapy. Four of the 24 patients with second or third degree of laryngeal obstruction required prophylactic tracheostomy. One patient in granulomatous stage with the second degree of laryngeal obstruction was cured with the combination of surgery and antibiotics therapy. Six patients in the scarring stage with laryngeal stenosis were cured with reconstruction surgery. One patient treated with radiotherapy recurred in the fourth year after treatment, and one patient failed to antibiotics therapy cured with radiotherapy combined with antibiotics therapy. CONCLUSIONS: Scleroma may involve the larynx and cause dysphonia and laryngeal obstruction. Antibiotics therapy is effective in most cases with laryngeal scleroma, and the long-time follow-up after treatment were necessary. Laryngeal reconstructions were necessary for the patients with cicatrical laryngeal stenosis.

Adolescent↗
PubMed2003

[Treatment of head and neck squamous cell carcinoma by recombinant adenovirus-p53 combined with radiotherapy: a phase II clinical trial of 42 cases].

OBJECTIVE: To evaluate the efficacy and safety of recombinant adenovirus-p53 (Adp53, SBN-1) combined with radiotherapy in treatment of head and neck squamous cell carcinoma (HNSCC). METHODS: Forty-two patients with HNSCC were randomly divided into 2 groups: gene therapy + radiotherapy group (GTRT group. n = 20, SBN-1 solution 1 x 10(12) VP was injected intratumorally once a week for 8 weeks and radiotherapy was begun since the 3rd day of gene therapy 5 fractions a week with the with the fraction dosage of 2 Gy and total dosage of 70 GY) and radiotherapy group (RT group. n = 22, the above regimen of radiotherapy was conducted). CT was conducted 5 weeks and 8 weeks after the beginning of treatment and 2 months after the finish of treatment (validation point) to calculate the size of tumor. Patients were monitored for adverse event and serum level of anti-adenoviral antibody. A comparative study was also performed on the immediate response rate by CT at the times when the dosages of 40 Gy and 70 Gy had been given. RESULTS: The average tumor reduction rates were (63 +/- 17)%, (82 +/- 18)%, and (90 +/- 16)% at the 40 Gy time point, 70 Gy time point, and validation point respectively in the GTRT group, all higher than those in the RT group (37 +/- 26)%, (62 +/- 39)%, and (70 +/- 34)% respectively, all P < 0.05. Random control study showed that the radio-sensitized enhancement rate was 1.72 at 40 Gy time point and the CR rate of the GRTR group at the validation point was 1.68 times higher than that of the RT group. Self-controlled study showed that the SBN-1 radio-sensitized enhancement ratio in the 4 GTRT group was 1.69 at 40 Gy time point and the CR rate of the GTRT group at validation point was 253% that of the RT group (P < 0.01). No dose-limiting toxicity and adverse events were noted, except transient fever after SBN-1 administration. CONCLUSION: A potentially effective gene therapeutic agent for HNSCC treatment, intratumoral injection of SBN-1 is safe.

Adenoviridae↗
PubMed2003

[Transdermal fentanyl for the management of cancer pain: a survey of 1,664 elderly patients].

OBJECTIVE: To evaluate the effects and side effects of transdermal fentanyl for the elderly patients with cancer pain. METHODS: A multicenter clinical test was conducted among 1,664 patients with cancer pain, aged 65 - 90 with a median age of 71, 879 (52.8%) of which used opioid for the first time, from 136 hospitals in 23 provinces in China. All patients received transdermal fentanyl to treat cancer pain with the mean dose of fentanyl of 31.34 micro g/h (25 - 150 micro g/h) initially, and 40.59 micro g/h and 47.50 micro g/h (25 - 200 micro g/h) at day 15 and day 30. They were asked to record the attacks of pain, quality of life, and any side effects of the treatment. RESULTS: The baseline pain intensity score was 7.34. On days 1, 3, 6, 9, 15, and 30, the mean pain scores were decreased to 3.82, 2.80, 2.43, 2.11, 1.83, and 1.64 (all P < 0.01) respectively. The effective rate was 97.18%. The fine life quality rate was 25.4% before treatment, and was 71.15% and 73.04% at day 15 and day 30 (both P < 0.01). The commonest side effects included constipation (10.70%), nausea (11.96%), dizziness (6.85%), vomiting (3.85%), sleepiness (2.40%), and respiratory depression (0.12%). The incidence of constipation was related with age, the incidence of vomiting and difficulty of urination was related with gender. 86.2% patients preferred to receive transdermal fentanyl. CONCLUSION: Safe, convenient, and capable to improve the quality of life, transdermal fentanyl is effective and worth recommending as a first-line drug for the treatment of elderly patients with moderate to severe cancer pain. The initial dose is recommended as 25 micro g/h.

Administration, Cutaneous↗
PubMed2003

Modeling of the whole expanded-bed protein adsorption process with yeast cell suspensions as feedstock.

Expanded bed adsorption of bovine serum albumin (BSA) directly from a feedstock containing whole yeast cells has been investigated with an anion-exchanger DEAE Spherodex M. In the presence of 6% (w/w) yeast cells, the axial liquid-phase dispersion coefficient was found in the order of 10(-6) m2/s, which felled into the common range of 1.0 x 10(-6)-1.0 x 10(-5) m2/s observed previously without the use of cell suspensions as mobile phase. We found that the static and dynamic binding capacity of BSA decreased with increasing the yeast cell concentration due to the competitive adsorption of cells onto the outer surface of the anion-exchanger. However, because of the small size of the adsorbent, the large pore diffusivity of protein and the favorable column efficiency (low axial dispersion coefficient), the dynamic binding capacity of BSA in the presence of 6% (w/w) cells in the expanded bed reached 86% that of the equilibrium adsorption density. Then, the whole expanded bed adsorption process of BSA in the presence of cells, including feedstock loading, washing and elution steps, was predicted using a mathematical model with parameters all determined independently. In the elution stage, the steric mass-action adsorption isotherm with salt concentration as one of the model parameters was used to predict the step-gradient elution process with salt concentration increases. Computer simulations showed that the model was in good agreement with the experimental results for the whole operation process.

Adsorption↗
PubMed2003

Phase III study of letrozole versus tamoxifen as first-line therapy of advanced breast cancer in postmenopausal women: analysis of survival and update of efficacy from the International Letrozole Breast Cancer Group.

PURPOSE: To analyze overall survival (OS) and update efficacy data for letrozole versus tamoxifen as first-line therapy in postmenopausal women with locally advanced or metastatic breast cancer. PATIENTS AND METHODS: This multicenter phase III trial randomly assigned 916 patients with hormone receptor-positive or unknown tumors letrozole 2.5 mg (n = 458) or tamoxifen 20 mg (n = 458) daily until disease progression. Optional cross-over was permitted at the treating physician's discretion. This report updates efficacy at a median follow-up of 32 months. RESULTS: The superiority of letrozole to tamoxifen was confirmed for time to progression (median, 9.4 v 6.0 months, respectively; P <.0001), time to treatment failure (median, 9 v 5.7 months, respectively; P <.0001), overall objective response rate (32% v 21%, respectively; P =.0002), and overall clinical benefit. Median OS was slightly prolonged for the randomized letrozole arm (34 v 30 months, respectively). Although this difference in OS is not significant, survival was improved in the randomized letrozole arm over the first 2 years of the study. Approximately one half of the patients in each arm crossed over. Total duration of endocrine therapy ("time to chemotherapy") was significantly longer (P =.005) for patients initially on letrozole (median, 16 months) than for patients initially on tamoxifen (median, 9 months). Time to worsening of Karnofsky performance score was significantly delayed with letrozole compared with tamoxifen (P =.001). CONCLUSION: This study documents the superiority of letrozole over tamoxifen in first-line endocrine therapy in postmenopausal women with advanced breast cancer.

Antineoplastic Agents↗
PubMed2003

An artificially designed pore-forming protein with anti-tumor effects.

Protein engineering is an emerging area that has expanded our understanding of protein folding and laid the groundwork for the creation of unprecedented structures with unique functions. We previously designed the first native-like pore-forming protein, small globular protein (SGP). We show here that this artificially engineered protein has membrane-disrupting properties and anti-tumor activity in several cancer animal models. We propose and validate a mechanism for the selectivity of SGP toward cell membranes in tumors. SGP is the prototype for a new class of artificial proteins designed for therapeutic applications.

Amino Acid Sequence↗
PubMed2003

Modeling of the salt effects on hydrophobic adsorption equilibrium of protein.

A two-state protein model is proposed to describe the salt effects on protein adsorption equilibrium on hydrophobic media. This model assumes that protein molecules exist in two equilibrium states in a salt solution, that is, hydrated and dehydrated states, and only the dehydrated-state protein can bind to hydrophobic ligands. In terms of the two-state protein hypothesis and the steric mass-action theory, protein adsorption equilibrium on hydrophobic media is formulated by a five-parameter equation. The model is demonstrated with the adsorption of bovine serum albumin to Phenyl Sepharose gels as a model system. The effects of salt type (sodium chloride, sodium sulfate and ammonium sulfate) on the model parameters are discussed. Then, the model formulism is simplified in terms of the small magnitude of the protein dehydration equilibrium constant in the model. This simplification has returned the model derived on the basis of the two-state protein hypothesis to its original mechanism of salt effects on the hydrophobic adsorption of protein. This simplified model also creates satisfactory prediction of protein adsorption isotherms.

Adsorption↗
PubMed2003

Luminescence-based whole-cell-sensing systems for cadmium and lead using genetically engineered bacteria.

Whole-cell-based sensing systems that respond to cadmium and lead ions have been designed and developed using genetically engineered bacteria. These systems take advantage of the ability of certain bacteria to survive in environments polluted with cadmium and lead ions. The bacteria used in this investigation have been genetically engineered to produce reporter proteins in response to the toxic ions. This was achieved by modifying a strain of Escherichia colito harbor plasmids pYSC1 and pYS2/pYSG1. In these dual-plasmid-based sensing systems, the expression of the reporters beta-galactosidase and red-shifted green fluorescent protein (rs-GFP) was controlled by CadC, the regulatory protein of the cad operon. Regulation of the expression of the reporter proteins is related to the amount of cadmium and lead ions employed to induce the bacteria. The bacterial sensing systems were found to respond to cadmium, lead, and zinc ions, and had no significant response to nickel, copper, manganese, and cobalt.

Biosensing Techniques↗