Biomedical subjects

Yun Duan

Publications and source records attributed to Yun Duan.

10 recordsLinked to original sources

PubMed2006

[Infection pathogen analysis of 2388 patients in an open hematology ward from 1993 to 2004].

OBJECTIVE: To investigate the incidence of infection and pathogens in hematology ward. METHODS: The data of incidence, pathogen, and outcome of infection of 2388 hospitalized patients in an open hematology ward of Peking Union Medical College Hospital from 1993 to 2004 were analyzed retrospectively. RESULTS: The overall incidence of infection was 34.3% according to the person-times of hospitalization, 24.4% for nosocomial infection and 9.9% for community-acquired infection. Most of the pathogenic bacteria of the nosocomial infection were Gram negative. The most common bacteria in the sputum samples included Enterobacter (27%), Pseudomonas aeruginosa (16%) and coagulase negative Staphylococcus (MRSCoN, 12%), the most common bacteria in the blood samples included Escherichia coli (43%), Enterobacter cloacae (11%), and Klebsiella (11%). Whereas in the community-acquired infection the most common bacteria in the sputum samples were Haemophilus parainfluenzae (15%), MRSCoN (28%), and Staphylococcus epidermidis (10%), and the most common bacteria in the blood samples were MRSCoN (28%), E. coli (28%), and Klebsiella (9.4%). Fungi were more often found in nosocomial infection, especially in the sputum samples. 12-year follow up showed that in nosocomial infection Pseudomonas aeruginosa remained the most common bacteria in the sputum samples, whereas E. coli and Enterobacter cloacae became the major bacteria in the blood samples. In community-acquired infection, the proportion of Staphylococcus aureus, that of Klebsiella in blood samples, and that of E. coli in throat swab samples increased in recent years. The incidence of fungi infection had increased in both nosocomial infection and community acquired infection. The mortality of nosocomial infection was 6.1%, higher than that of the community-acquired infection, however, not statistically significant (P = 0.17). There was a trend of decrease in the mortality of community-acquired infection but did not in the nosocomial infection. CONCLUSION: The patients in hematology ward are susceptible to infection, especially nosocomial infection that has a higher mortality rate in comparison with the community-acquired infection, however, not statistically significant. The pathogens of nosocomial infection are most likely G- bacteria, fungi and other bacteria resistant to most antibiotics. The mortality rate of nosocomial infection remains almost unchanged in the 12-year follow up.

Adolescent↗

PubMed2006

Association study of serotonin 2A receptor (5-HT2A) gene with schizophrenia and suicidal behavior using systematic meta-analysis.

Serotonin 2A receptor (5-HT2A) gene was implicated to be associated with both schizophrenia and suicidal behavior due to its role of key neurotransmitter in many physiologic processes. Association studies were reported in different populations, however, a great number of subsequent studies have produced contrary results, possibly reflecting inadequate statistical power. With the cumulative data in recent years in both European and Asian populations, particularly in Asian populations, it was necessary to carry out a comprehensive analysis of previous findings. The meta-analysis, therefore, combined all English and Chinese studies using multiple research methods published up to July 2005 to give a new picture of the role of the 5-HT2A gene. Compared with significant results reported previously, the current large samples (73 studies in all) failed to find significant association of the T102C polymorphism with either schizophrenia or suicidal behavior. Evidence of significant association was only detected between A-1438G and suicidal behavior. The current study did not support the association of the 5-HT2A gene with either schizophrenia or suicidal behavior.

Alleles↗

PubMed2005

Association study of the A2M and LRP1 Genes with Alzheimer disease in the Han Chinese.

BACKGROUND: Low-density lipoprotein receptor-related protein 1 (LRP1) and alpha-2-macroglobulin (A2M) are two plausible candidate genes for Alzheimer disease (AD) based on their important biological function and positional information. To date, numerous studies have investigated their possible association with AD but the results are controversial. METHODS: To investigate the potential genetic contribution of the two genes in the Han Chinese population, we performed a case-control association study using 10 polymorphisms (4 in LRP1 and 6 in A2M) that span approximately the whole corresponding gene. RESULTS: Comparison of allele, genotype, and haplotype frequencies for polymorphisms in A2M revealed no significant differences between patients and control subjects. For the LRP1 gene, however, we found an overrepresentation of the CTCG haplotype in the control group (p = .002). The difference was still of statistical significance in the apolipoprotein E (APOE) epsilon 4 negative subjects (p(CTCG) = .003). Multiple logistic regression analysis did not show any evidence of synergism between A2M, LRP1, and APOE. CONCLUSIONS: Our results indicate that the CTCG haplotype of LRP1 may reduce the risk of late-onset AD, but A2M is not associated with this disease in the Han Chinese population.

Aged↗

PubMed2005

Association of the carboxyl-terminal PDZ ligand of neuronal nitric oxide synthase gene with schizophrenia in the Chinese Han population.

Several independent linkage studies have demonstrated that the 1q22 region is likely to harbor candidate schizophrenia susceptibility genes. Recently, some genetic variants within CAPON have been reported as exhibiting significant linkage disequilibrium to schizophrenia in Canadian familial-schizophrenia pedigrees. We examined nine single nucleotide polymorphisms (SNPs), which span an approximately 236-kb region of CAPON, in 664 schizophrenia cases and 941 controls in the Chinese Han population. We detected a significant difference in allele distributions of SNP rs348624 (P = 0.000017). Moreover, the overall frequency of haplotypes constructed from three SNPs including rs348624 showed significant difference between cases and controls (P = 0.000025). Our findings indicate that CAPON gene may be a candidate susceptibility gene for schizophrenia in Chinese Han population, and also provide further support for the potential importance of NMDAR-mediated glutamatergic transmission in the etiology of schizophrenia.

Adaptor Proteins, Signal Transducing↗

PubMed2005

Predicting protein subcellular location using digital signal processing.

The biological functions of a protein are closely related to its attributes in a cell. With the rapid accumulation of newly found protein sequence data in databanks, it is highly desirable to develop an automated method for predicting the subcellular location of proteins. The establishment of such a predictor will expedite the functional determination of newly found proteins and the process of prioritizing genes and proteins identified by genomic efforts as potential molecular targets for drug design. The traditional algorithms for predicting these attributes were based solely on amino acid composition in which no sequence order effect was taken into account. To improve the prediction quality, it is necessary to incorporate such an effect. However, the number of possible patterns in protein sequences is extremely large, posing a formidable difficulty for realizing this goal. To deal with such difficulty, a well-developed tool in digital signal processing named digital Fourier transform (DFT) [1] was introduced. After being translated to a digital signal according to the hydrophobicity of each amino acid, a protein was analyzed by DFT within the frequency domain. A set of frequency spectrum parameters, thus obtained, were regarded as the factors to represent the sequence order effect. A significant improvement in prediction quality was observed by incorporating the frequency spectrum parameters with the conventional amino acid composition. One of the crucial merits of this approach is that many existing tools in mathematics and engineering can be easily applied in the predicting process. It is anticipated that digital signal processing may serve as a useful vehicle for many other protein science areas.

Algorithms↗

PubMed2004

[Treatment of severe systemic autoimmune diseases with autologous peripheral blood stem cell transplantation].

OBJECTIVE: To investigate the feasibility, efficacy and safety of high dose immunosuppressive therapy (HDIT) and autologous peripheral blood stem cell transplantation (PBSCT) with CD(34)(+) cell selection in patients with refractory and severe autoimmune diseases. METHODS: Twenty-one patients with SLE, RA, pSS, SSc or MCTD were enrolled in the study from 1999. Autologous haemopoietic stem cells were mobilized with CTX 3 approximately 4 g/m(2) and granulocyte colony stimulating factor (G-CSF). CD(34)(+) cells were selected by CliniMACS. After conditioning with CTX (200 mg/kg) and pig antithymocyte globulin (ATG, 90 mg/kg) or CTX (150 mg/kg) and total body irradiation (TBI, 4 approximately 6 Gy), the enriched CD(34)(+) cells were reinfused. RESULTS: All patients completed the mobilization and leukapheresis procedures successfully, and proceeded to receive conditioning and transplantation. Two patients died of complication related to transplantation, one is CMV infection, the other is severe pneumonia during the course of granulocyte deficiency. A MCTD patient completed the stem cell mobilization and died of severe pulmonary hypertension and heart failure before CD(34)(+) cells reinfusing. Two SLE patients relapsed in 26, 37 months respectively and a RA patient relapsed in 15 months after transplantation. Other patients got improved, with SLE-DAI score decreasing from 17 to 4 score and proteinuria decreasing from 6.7 g to 2.3 g in SLE patients; DAS28 score from 7.9 to 2.1 in RA patient; Symptom improved and lab results recovered in SS. CONCLUSION: High dose immunosuppressive therapy followed by autologous peripheral blood stem cell transplantation with CD(34)(+) cell selection is feasible and relative safe. Patients remain free from disease active and improved continuously. Some patients could relapse after transplantation. Long-term effect need to be further observed.

Arthritis, Rheumatoid↗

PubMed2004

Association of G72/G30 with schizophrenia in the Chinese population.

Recently, the G72 gene was reported to be associated with schizophrenia in the French Canadian and Russian populations. Here, we report the results obtained from the study of six single-nucleotide polymorphisms (SNPs: rs3916965, rs3916967, rs2391191, rs1935062, rs778293, and rs3918342), which span an 82-kb region covering the complementary DNA sequences of G72 and G30, in 537 schizophrenia cases and 538 controls of the Han Chinese. In this work, we have identified statistically significant differences in allele distributions of two markers rs3916965 (P = 0.019) and rs2391191 (P = 0.0010), and a highly significant association between haplotype AGAC of the G72/G30 locus (P = 1.7 x 10(-4)) and schizophrenia. Our data provide further evidence that markers of the G72/G30 genes are associated with schizophrenia in a non-Caucasian population.

Adult↗

PubMed2004

Understanding SARS with Wolfram approach.

Stepping acquired immunodeficiency syndrome (AIDS), severe acute respiratory syndrome (SARS) as another type of disease has been threatening mankind since late last year. Many scientists worldwide are making great efforts to study the etiology of this disease with different approaches. 13 species of SARS virus have been sequenced. However, most people still largely rely on the traditional methods with some disadvantages. In this work, we used Wolfram approach to study the relationship among SARS viruses and between SARS viruses and other types of viruses, the effect of variations on the whole genome and the advantages in the analysis of SARS based on this novel approach. As a result, the similarities between SARS viruses and other coronaviruses are not really higher than those between SARS viruses and non-coronaviruses.

Algorithms↗

PubMed2004

Genetic structure adds power to detect schizophrenia susceptibility at SLIT3 in the Chinese Han population.

The Chinese Han population, the largest population in the world, has traditionally been geographically divided into two parts, the Southern Han and Northern Han. In practice, however, these commonly used ethnic labels are both insufficient and inaccurate as descriptors of inferred genetic clustering, and can lead to the observation of "spurious association" as well as the concealment of real association. In this study, we attempted to address this problem by using 14 microsatellite markers to reconstruct the population genetic structure in 768 Han Chinese samples, including 384 Southern Han and 384 Northern Han, and in samples from Chinese minorities including 48 Yao and 48 BouYei subjects. Furthermore, with a dense set of markers around the region 5q34-35, we built fine-scale haplotype networks for each population/subpopulation and tested for association to schizophrenia susceptibility. We found that more variants in SLIT3 tend to associate with schizophrenia susceptibility in the genetically structured samples, compared to geographically structured samples and samples without identified population substructure. Our results imply that identifying the hidden genetic substructure adds power when detecting association, and suggest that SLIT3 or a nearby gene is associated with schizophrenia.

Adult↗

PubMed2003

[A preliminary study on the treatment of severe autoimmune disease by autologous peripheral CD(34)(+) cell transplantation].

OBJECTIVE: To evaluate the feasibility of autologous peripheral CD(34)(+) cell transplantation for the treatment of severe autoimmune disease. METHODS: Ten patients received mobilized and purified CD(34)(+) cells transplantation. The mobilization regimen was CTX plus rhG-CSF and the CD(34)(+) cells were selected by CliniMACS. (1.98 +/- 0.95) x 10(8) CD(34)(+) cells were obtained. The purity of CD(34)(+) cells was (91.4 +/- 10.6)% and the recovering rate was (60.5 +/- 19.8)%. The conditioning regimens were CTX (200 mg/kg) plus ATG (90 mg/kg) or CTX (150 mg/kg) plus TBI (4 - 6 Gy). (2.14 +/- 1.05) x 10(6)/kg CD(34)(+) cells were infused. The time of ANC >or= 0.5 x 10(9)/L was 8.6 +/- 2.5 days, and platelet >or= 20 x 10(9)/L was 9.0 +/- 5.2 days. After the hematopoietic recovery, the levels of CD(3)(+) T cell, CD(19)(+) B cells and CD(16)(+)CD(56)(+) NK cells were all below that of pre-transplantation. The main transplant-related complication was CMV infection. The transplant-related mortality was 2/10. All patients who survived showed improvement of the disease with DAI score decreasing from 17 to 4 in systemic lupus erythematosus patients, DAS 28 score from 6.4 to 1.8 in rheumatoid arthritis patients. CONCLUSION: The result suggests that autologous peripheral CD(34)(+) cell transplantation is an alternative choice for the treatment of severe autoimmune disease. The short-term outcome is satisfying.

Adolescent↗