Search PubMed⌕ Search

Biomedical subjects

Yan Zhang

Publications and source records attributed to Yan Zhang.

At least 397 records · Page 22Linked to original sources
PubMed2004

[Molecular characteristics of Acanthamoeba strains from keratitis patients].

OBJECTIVE: To study the molecular characteristics of Acanthamoeba strains isolated from keratitis patients. METHODS: Twenty six Acanthamoeba strains were isolated from corneal ulcers between 1994 and 2002. Partial genome DNA sequences of all strains of Acanthamoeba were amplified using PCR and then the PCR products were sequenced. The partial DNA sequences were analyzed by software Clustal X and MEGA2. The results of Acanthamoeba obtained from Beijing Tongren Hospital were compared with strains from other countries and districts. RESULTS: Of 26 Acanthamoeba strains isolated from the patients, 25 (96%) were 18S rDNA (Rns) genotype T4 and one (4%) was T3. These results were similar to those obtained from other countries and districts. CONCLUSIONS: According to the Rns genotype classification criterion, most of Acanthamoeba strains isolated from keratitis patients in Beijing are genotype T4 and only few of these strains are genotype T3. The Acanthamoeba infecting the cornea might belong to the specific 18S rDNA genotype.

Acanthamoeba↗
PubMed2004

[Clinical significance of antiphospholipid antibody in pediatric patients and review of literature].

OBJECTIVE: Antiphospholipid antibody (APL) is a particularly important laboratory diagnostic criterion for antiphospholipid syndrome (APS). The significances of positive APL in childhood are seldom reported nor fully understood. The purpose of this study was to analyze 13 cases with positive APL seen in our hospital and to study the relationship between the positive rates of APL and various clinical diseases especially systemic lupus erythematosus (SLE) in order to improve the clinical diagnoses and treatment level of APS in children. METHODS: The clinical data collected from 2000 to 2002 of 13 hospitalized children with positive APL were retrospectively evaluated. Enzyme linked immunosorbent assay (ELISA) and indirect immunofluorescence technique were used respectively to detect APL and antineutrophil cytoplasmic autoantibodies (ANCA) of sera from those children. Other various indexes were also detected according to different characteristics of different diseases. RESULTS: Eight cases had SLE; 2 had acute post-streptococcal infections. The other 3 cases did not show any evidences of primary diseases; they probably had primary APS. SLE was the most common primary diseases to cause development of APL and the cases with SLE showed more severe cutaneous vasculitis than SLE patients who were negative for APL. There was no significant relationship between the positive rates of APL and that of ANCA. Eight APL positive cases complicated with thrombocytopenia and bleeding were treated with high dosage of immunoglobulin [400 mg/(kg.d), for 3 - 5 d] intravenously; the clinical conditions of these cases were ameliorated soon. While the 5 cases who had thrombotic vasculitis and thromboembolism were treated with anticoagulant and antithrombotic therapy with low molecular weight heparin [50 - 100 U/(kg.d)], which led to good clinical effects. CONCLUSIONS: The clinical manifestations of children positive for APL were somehow different from those of adults. Positive APL itself may be nonspecific, it can occur from different causes of diseases. APL detection may be useful to suggest anticoagulant and/or antithrombosis therapy. Treatments for APS should be variable according to different causes and severity of diseases, in the cases of thrombocytopenia and bleeding, high dose intravenous immunoglobulin should be given as soon as possible, while in the cases of thrombotic vasculitis and thromboembolism, anticoagulant and antithrombotic therapy should be given soon.

Adult↗
PubMed2004

[Study on karyotype of 306 cases of myelodysplastic syndrome].

The purpose of this study was to explore the significance of abnormal karyotype in diagnosis and prognosis estimation of myelodysplastic syndrome (MDS). Chromosome analysis were performed in 306 cases of MDS using the short-term culture of bone marrow cell and G-banding technique, and in partial cases FISH technique was used for this analysis. 93 out of 306 cases were followed up. The results showed that 144 cases (47.1%) had clonal chromosome aberrations. The most common chromosomal aberrations included +8, translocation, complex or high complex karyotype, -7/7q-, 20q-/-20, trisomy 1 or partial trisomy 1, +11/+11q-, -9/9q-, +9/9q+, -Y, dup(1q), +21. The rate of abnormal karyotype in refractory anemia with erythroblasts (RAEB) and refractory anemia with erythroblasts-transformation (RAEBT) were much higher than in refractory anemia (RA) and refractory anemia with sideroblasts (RAS) (P < 0.05). The rate of abnormal karyotype among those cases with mutagen contact history were higher than those in cases without mutagen contact history. The patients with abnormal karyotype had a mean survival time much shorter than patients with normal karyotype (P < 0.005) and had a higher risk transforming into acute leukemia (P < 0.05). The worst outcome was observed in those patients with a complex or high complex karyotype, -7/7q- and trisomy 11. In conclusion, MDS is highly heterogeneous disorders and karyotype analysis is helpful for its diagnosis, treatment selection and prognosis estimation.

Adolescent↗
PubMed2004

[The analysis of HLA-B15 and B40 antigen polymorphism in Xi'an].

AIM: To study the distribution character of HLA-B15 and B40 in Xi'an population. METHODS: PCR-SSP and reverse PCR-SSOP reaction pattern were used to type the HLA-B15 and B40 alleles of 3 601 blood samples in Xi an. RESULTS: HLA-B15 and B40 gene frequencies were 0.1483 and 0.1414, respectively, among 3 601 blood samples from Xi'an population which take up 57.91% in HLA-B alleles. CONCLUSION: The distribution character of HLA-B15 and B40 alleles in Xi'an population were different compared with other populations.

Black or African American↗
PubMed2004

[Reconstruction of rabbit corneal stroma using tissue engineering technique].

OBJECTIVE: Reconstruct corneal stroma by tissue engineering. METHODS: Primary corneal stromal cells were isolated from newborn rabbit cornea. When the cultured cells reaching confluence, the stromal cells were mixed with polyglycolic acid (PGA) to form a cell-scaffold construct. After 1 week in vitro culture, the constructs were implanted into mother rabbit corneal stroma. Parts of corneal stromal cells were transfected with GFP gene as mark of transplanted cells. Tissues were harvested at 8 weeks for transmission electron microscopy (TEM), histology and Western blot evaluation. In control, PGA alone was implanted into the other cornea. RESULTS: The engineered corneal stroma became transparent gradually over a period of 8 weeks. The histology of engineered stromal lamellar was relatively similar to that of natural one, no significant differences were found in the diameter of cornea collagen fiber [(29.4 +/- 4.7) nm] in experimental rabbits compared with control [(28.5 +/- 3.5) nm], Student's t-test: P = 0.1316 > 0.05. TEM demonstrated that collagen fibrils deposited in engineered stroma had a similar diameter compared to that of normal counterpart. In addition, Western blot showed the positive expression of type I collagen in the collagen fibrils. In contrast, no new stroma tissue was formed when PGA alone implanted. A green colored stroma was observed when engineered with GFP-labeled cells under fluorescence light microscope. CONCLUSION: The results demonstrate that nearly transparent corneal stroma can be obtained by the technique of cornea engineering.

Animals↗
PubMed2004

Effects of beta-aescin on apoptosis induced by transient focal cerebral ischemia in rats.

AIM: To investigate the effects of beta-aescin on apoptosis induced by transient focal brain ischemia in rats. METHODS: Rats were pretreated with beta-aescin for 7 d and then subjected to brain ischemia/reperfusion (I/R) injury induced by a middle cerebral artery occlusion. After 2 h ischemia and 24 h reperfusion, Hematoxylin-Eosin (HE) staining, in situ end-labeling of nuclear DNA fragmentation (TUNEL) were employed to determine the level of apoptosis. The expressions of caspase-3 and Bcl-2 in the cortex were determined by immunohistochemistry and Western blot. The release of cytochrome c was analyzed by Western blot. RESULTS: The increased numbers of HE- and TUNEL-positive staining cells were significantly observed at 24 h after reperfusion. The immunoreactivity was inhibited by beta-aescin (30, 60 mg/kg) (P<0.01 or P<0.05 vs vehicle-treated). After cerebral I/R, cytochrome c was released into the cytosol and caspase-3 was activated, whereas Bcl-2 expression was inhibited. beta-Aescin (30, 60 mg/kg) markedly inhibited the expression of caspase-3 and the release of cytochrome c, and up-regulated the expression of Bcl-2 (P<0.05, P<0.01 vs vehicle-treated). CONCLUSION: beta-Aescin could potently inhibit caspase-3 activation and the release of cytochrome c, increasing the expression of Bcl-2 after cerebral I/R in rats. These findings on the inhibitory effects of beta-aescin on brain ischemic injury-induced apoptosis might have important theoretical basis for the treatment on ischemic cerebrovascular diseases.

Animals↗
PubMed2004

[Effect of different dosage of vitamin A supplement on anti-oxidative activity and the fluidity of erythrocyte membrane in rats].

OBJECTIVE: To investigating the effect of vitamin A (VA)at different dosage of vitamin A on anti-oxidative activity and the fluidity of erythrocyte membrane in rats and safe dosage. METHODS: Wistar rats selected for VA supplement trial were randomly divided into four groups. The first group was no VA supplement as a control, and the second, third, forth groups were daily supplemented with VA 11.43, 42.86 and 142.86 microg RE/kg respectively. The trial lasted 8 weeks. Vitamin A was dissolved in soybean oil and daily given to animals by gavage. The blood samples were collected at the end of the trial. The level of plasma VA was analyzed by fluorescent spectrometry. SOD, GSH and MDA in plasma were analyzed. The blood erythrocyte membrane fluidity was detected by fluorescence polarization method. RESULTS: The results showed that plasma retinol levels increased with increase of vitamin A. After 8 week supplement, SOD activities in the second and the third groups were lower than those of the first and the fourth group (P < 0.01), which was the highest in the four groups (P < 0.01). The level of plasma MDA in the third was the lowest (P 0.01). GSH-Px activity was higher in the third group than other three groups (P < 0.01). Moreover, P (fluorescence polarization) was lower in 42.86 microg RE/kg group than other three groups, and P significantly increased in the fourth group (P < 0.01), which indicates that the erythrocyte membrane fluidity increased significantly after 42.86 microg RE/kg vitamin A supplement. CONCLUSION: The supplement of 42.86 microg RE/kg VA could improve anti-oxidative activity and enhance erythrocyte membrane fluidity. Overtake vitamin A could produce a poisoning effect and a stronger oxidative damage.

Animals↗
PubMed2004

Significant associations of the alpha-adducin gene Gly460Trp polymorphism with serum bilirubin concentrations in Chinese essential hypertension patients.

We investigated associations of the Gly460Trp polymorphism of the alpha-adducin gene and concentrations of serum total bilirubin, serum direct bilirubin and serum unconjugated bilirubin in patients with essential hypertension from Anhui, China from September 2000 to January 2001. Compared to women with the Gly/Gly genotype and after adjustment for important covariates, women with the Trp/Trp genotype had lower mean concentrations of serum total bilirubin (beta = -1.2 micromol/L; P = 0.01), serum direct bilirubin (beta = - 0.4 micromol/L; P = 0.02) and serum unconjugated bilirubin (P = -0.8 micromol/L; P = 0.03). Among women in either the upper or lower quartiles of serum total bilirubin, serum direct bilirubin and serum unconjugated bilirubin and compared to those with the Gly/Gly genotype, women with the Trp/Trp genotype had higher odds of being in the lower quartile of concentrations of serum total bilirubin (odds ratio = 4.0; 95 percent confidence interval: 1.6 - 10.2; P < 0.01), serum direct bilirubin (odds ratio = 4.0; 95 percent confidence: 1.6 - 9.7; P < 0.01) and serum unconjugated bilirubin (odds ratio = 2.7; 95 percent confidence interval: 1.1 - 6.7; P = 0.03) after adjustment for important covariates. We did not observe any significant associations in these models for men. We concluded that the Trp/Trp genotype of alpha-adducin Gly460Trp was associated with lower serum bilirubin concentrations in this group of Chinese women with essential hypertension. Women with the Trp/Trp genotype of alpha-adducin Gly460Trp might have increased risk for cardiovascular diseases due to lower concentrations of serum bilirubin.

Adult↗
PubMed2004

[Detection of HCV antibody in 12 280 inpatients admitted not for infectious diseases].

OBJECTIVE: To study the status of hepatitis C virus (HCV) infection in the inpatients scheduled for operations and blood transfusion, thereby to avoid potential nosocomial infection and possible medical disputes. METHODS: Enzyme-linked immunosorbent assay (ELISA) was used to detect HCV antibody and HBsAg in the blood samples from 12 280 inpatients admitted in other medical departments than the department of infectious disease, who were scheduled for operations and blood transfusion. RESULTS: In the 12 280 blood samples, the positivity rate of HCV antibody was 1.03%, and those of both HBsAg and HCV was 0.17%. CONCLUSION: The positivity rate of HCV antibody is higher in these patients than in the healthy population, suggesting the necessity of HCV antibody detection in patients admitted not for infectious diseases before operation and blood transfusion.

Adolescent↗
PubMed2004

[The effect of HSV-tk/GCV on hepatic specific damage driven by murine ALB promoter/enhancer].

The recombinant vector (pLLTK), containing murine serum albumin (ALB) gene promoter/enhancer directing the herpes simplex virus thymidine kinase (HSV-tk) gene expression was constructed to study its effect on hepatic cell-specific damage. Firstly,in order to compare the hepatic cell-specific transcriptional activity, three vectors were constructed in which green fluorescent protein (GFP) gene was used as a reporter marker. Vector pLE was driven by murine serum ALB gene promoter,whereas pLLE contained not only murine ALB promoter but also an enhancer located at upstream of the promoter was included. In the meanwhile, the vector pLEL had a murine ALB promoter and enhancer placed at the downstream from GFP. After transfected into Hep-G2 (a human hepatic cell line) and HC-11 (a murine breast epithelial cell line), GFP expression was examined by using fluorescence microscope as well as flow cytometer. Secondly, the vector pLLTK was used to observe the killing effect on Hep-G2 cells. The results demonstrated that ALB promoter/enhancer was able to direct hepatic cell-specific GFP expression. Furthermore, HSV-tk expression in Hep-G2 cells was ganciclovir (GCV)sensitive. After seven days of culture with GCV, pLLTK-transfected Hep-G2 cells showed an obvious cell death (53%) when detected by 3-4,5 dimethylthiozol-2-yl-2, 5-diphenyl tetrazolium bromide colorimetry (MTT) assay. Compared to the untreated group, there were no obvious changes in cellular growth inhibition rate in the Hep-G2 cells transfected with a blank control vector pcDNA3. 1 (only 2% of cells appeared cell death). All these results indicated that the above constructs were hepatocyte-specific. It therefore paves a way for further creating a liver-specific damage animal model by transgenic approach using HSV-tk gene expression driven by the ALB promoter/enhancer.

Animals↗
PubMed2004

[Meta-analysis on the relationship between tobacco smoking, alcohol drinking and p53 alteration in cases with esophageal carcinoma].

OBJECTIVE: To investigate the relationship between tobacco smoking, drinking and p53 alteration in esophageal carcinoma. METHODS: Literature on the relationship between p53 alteration in esophageal carcinoma and tobacco smoking, drinking through Meta-analysis were reviewed. RESULTS: In 14 selected papers related to tobacco smoking, pooled odds ratio (OR) of tobacco smoking with P53 overexpression and p53 alteration were 1.99 (95% CI: 1.30- 3.06) and 1.64 (95% CI: 1.13 - 2.37), respectively (P < 0.05). Pooled OR of tobacco smoking with p53 mutation was 1.11 (95% CI: 0.47 - 2.76) (P > 0.05). In 11 selected papers on alcohol drinking, pooled OR of drinking with P53 overexpression, p53 mutation and p53 alteration were 1.30 (95% CI: 0.83 - 2.04), 1.13 (95% CI: 0.67 - 1.90) and 1.22 (95% CI: 0.87 - 1.72) respectively (P > 0.05). CONCLUSION: There were significant relations between tobacco smoking and p53 alteration while there were no significant relations between alcohol drinking and p53 alteration.

Alcohol Drinking↗
PubMed2004

[Construction and expression of regulatable recombinant adenovirus vector for mouse PLP-Ig chimeric protein].

AIM: To construct a regulatable recombinant adenovirus vector expressing mouse proteolipid protein (PLP)-Ig. METHODS: Total RNA was extracted from WT-1 hybridoma cells to clone Ig heavy chain Fc fragment gene. PCR was carried out to link PLP(139-151) gene and signal peptide with Fc fragment gene. pTRE-shuttle vector was used to ligate PLP-Ig gene and the backbone of the replication-incompetent adenoviral vector. After confirming the desired recombinant adenovirus by PCR and restriction endonuclease digestion analysis, it was packaged and propagated in HEK 293 cells. Tetracycline was used to regulate the expression of PLP-Ig, and Western blot was used to detect the gene expression. RESULTS: The expression of PLP-Ig was confirmed by Western blot and its expression could be regulated by tetracycline. CONCLUSION: The regulatable recombinant adenovirus vector for mouse PLP-Ig was constructed and expressed successfully, which lays the foundation for further study on gene therapy of EAE and induction of immune tolerance.

Adenoviridae↗
PubMed2004

[Age-related changes in growth and metabolism function of human costal chondrocytes cultured in vitro].

OBJECTIVE: To investigate the expressive changes of collagen I, II and aggrecan during the aging of the human costal chondrocytes cultured in vitro, in order to select the best chondrocytes for cartilage engineering. METHODS: The human costal chondrocytes from the different passages (P1-P5) were harvested. The morphological changes and cell proliferation rate were observed, and the quantity of glycosaminoglycans (GAGs) was examined in each passage with alcian blue precipitation. The expression of collagen I, II and aggrecan was measured with immunohistochemistry and RT-PCR method. RESULTS: From the third passage, the human costal chondrocytes were transformed into fibroblast-like cell morphology; and the GAGs content in each passage was decreased and became significantly low in the third passage. The expression of the collagen I, II was consistent in the protein level with that in the mRNA level. Before the second passage, the expression of collagen II was high while the collagen I was low. After the second passage, the expression of collagen II decreased while the collagen I increased. The expression of aggrecan was high before the third passage, and then became low in the fourth passage. CONCLUSION: With the examinations of the cell proliferating rate and cell functions in human chondrocytes cultured in vitro, the chondrocytes of the second passage seem suitable for human cartilage engineering.

Aggrecans↗
PubMed2004

[Clinical significance of continuous karyotyping in myelodysplastic syndromes].

OBJECTIVE: To explore the relationship between evolution of karyotype and clinical progress in myelodysplastic syndromes (MDS) and estimate the clinical outcomes of high risk patients received allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: Continuous karyotyping were performed using short-term culture of bone marrow cells and G-banding technique to follow up 41 cases of MDS patients. RESULTS: Karyotype analysis showed that 24 cases (58.5%) had clonal karyotypic abnormalities. In a median follow up of 34 months (7 approximately 72 months), 6 cases had karyotype evolution in 12 cases with clinical deterioration, while only one had karyotype evolution in 18 cases without clinical progression. The involved chromosomes included No. 2, 4, 7, 8, 10, 11, 17 and 21. Six out of 7 patients who received allo-HSCT attained complete remission and their abnormal karyotypes returned to normal. Four patients with clinical remission after therapy attained cytogenetic remission too. CONCLUSION: Karyotype evolution showed a strong relationship with clinical progress in MDS patients, and indicated a very poor prognosis. Patients with clinical progress had much higher incidence of clonal evolution than those with relatively stable clinical course. Allo-HSCT should be considered the first choice of therapy for MDS patients with clonal karyotypic abnormalities.

Adolescent↗
PubMed2004

[Unspecified peripheral T cell lymphoma with distinct lymphoid follicules].

OBJECTIVE: To investigate the morphological features and immunophenotype of unspecified peripheral T cell lymphoma with distinct lymphoid follicular growth pattern. METHODS: Three cases of peripheral T cell lymphoma with special pathohistological features were collected. Morphologic analysis and immunohistochemical staining for CD3, CD45RO, CD43, CD20, CD79a, cyclinD1, bcl-2, CD4, CD8 and S-100 were performed. PCR was used to study TCR gamma gene rearrangements. RESULTS: The main symptoms of all the three patients with the primary sites of cervix and lower jaw. There were intermittent fever and skin rashes in the course of the disease. Morphological study showed lymphoid follicular reactive hyperplasia, mantle zone disappear, prominent infiltration of marginal zones by medium-sized tumor cells with clear cytoplasm and significant nuclear atypia. The immunophenotypic profile confirmed that they were T cell lymphomas. TCR gamma gene rearrangements were found in all the three patients. CONCLUSION: In some unspecified peripheral T cell lymphomas, the distinct follicular growth pattern and incomplete effacement of the lymph node architecture make it necessary to differentiate them from reactive hyperplasia, marginal zone B cell lymphoma, follicular B cell lymphoma and mantle cell lymphoma.

Adult↗
PubMed2004

[Screening of angiotensin converting enzyme inhibitors from Salvia miltiorrhizae].

OBJECTIVE: To screen angiotensin converting enzyme inhibitor (ACEI) from traditional Chinese medicine, Salvia miltiorrhiza. METHOD: Hydrophilic and lipophilic fractions of S. miltiorrhiza were isolated, and their effective components were screened by a fluorimetric assay for inhibition of angiotensin converting enzyme (ACE). RESULT: Water-soluble fractions, total salvianolic acids and salvianolic acid B markedly decreased ACE activity of rabbit lung tissue. Their IC50 value were (2.45 +/- 0.07), (0.24 +/- 0.02), (0.02 +/- 0.01) g x L(-1) respectively. Lipophilic components or phenanthraquinones including tanshinone I and II showed no changes on the activity of ACE. CONCLUSION: S. miltiorrhiza inhibits angiotensin converting enzyme and its active components are in aqueous extract, in which the main were salvianolic acids including salvianolic acids B.

Angiotensin-Converting Enzyme Inhibitors↗