Biomedical subjects

Dong Xiang

Publications and source records attributed to Dong Xiang.

10 recordsLinked to original sources

PubMed2007

Lower low-density lipoprotein cholesterol levels are associated with Parkinson's disease.

The apolipoprotein E (APOE) epsilon2 allele has been associated with both Parkinson's disease (PD) and lower low-density lipoprotein cholesterol (LDL-C). We tested the hypothesis that lower LDL-C may be associated with PD. This case-control study used fasting lipid profiles obtained from 124 PD cases and 112 controls. The PD cases were recruited from consecutive cases presenting at our tertiary Movement Disorder Clinic, and the controls were recruited from the spouse populations of the same clinic. Multivariate odds ratios (ORs) and 95% confidence intervals (CIs) were calculated from unconditional logistic regressions, adjusting for age, gender, smoking status, and use of cholesterol-lowering agents. Lower LDL-C concentrations were associated with a higher occurrence of PD. Compared with participants with the highest LDL-C (> or =138 mg/dL), the OR was 2.2 (95% CI = 0.9-5.1) for participants with LDL-C of 115 to 137, 3.5 (95% CI = 1.6-8.1) for LDL-C of 93 to 114, and 2.6 (95% CI = 1.1-5.9) for LDL-C of < or = 92. Interestingly, use of either cholesterol-lowering drugs, or statins alone, was related to lower PD occurrence. Thus, our data provide preliminary evidence that low LDL-C may be associated with higher occurrence of PD, and/or that statin use may lower PD occurrence, either of which finding warrants further investigation.

Aged↗

PubMed2006

[Clinical application of the distally based sural island flap and myofasciocutaneous flap].

OBJECTIVE: To investigate the clinical efficiency of the distally based sural island flap and myofasciocutaneous flap in reconstruction of defect and osteomyelitic cavity of the ankle and foot. METHODS: From June 1997 to October 2004, 21 patients with soft tissue defects and osteomyelitis in the ankle and foot were treated with the distally based sural island flap and myofasciocutaneous flap. There were 20 males and 1 female aging from 6 to 78 years. The defect was caused by soft tissue defect trauma (18 cases) and electrical injury (3 cases). Among 21 patients, 17 were treated with island flaps, 4 by the myofasciocutaneous flap. The size of flaps ranged from 4 cm x 5 cm to 16 cm x 22 cm. The donor sites were closed directly in 4 cases. RESULTS: The flaps completely survived in 21 cases and healing by first intention was achieved. After a follow-up of 3-6 months, no complication occurred. The color and texture of the flaps were good. The appearance and the function were satisfactory. CONCLUSION: Distally based sural flap is a reliable flap. This flap has rich blood supply without sacrifice of major arteries. Flap elevation is easy. It is very useful in repairing large soft tissue defects of the lower leg, the ankle and the foot, especially in repairing deep soft tissue defects and osteomyelitic cavities.

Adolescent↗

PubMed2004

A robust toolkit for functional profiling of the yeast genome.

Study of mutant phenotypes is a fundamental method for understanding gene function. The construction of a near-complete collection of yeast knockouts (YKO) and the unique molecular barcodes (or TAGs) that identify each strain has enabled quantitative functional profiling of Saccharomyces cerevisiae. By using these TAGs and the SGA reporter, MFA1pr-HIS3, which facilitates conversion of heterozygous diploid YKO strains into haploid mutants, we have developed a set of highly efficient microarray-based techniques, collectively referred as dSLAM (diploid-based synthetic lethality analysis on microarrays), to probe genome-wide gene-chemical and gene-gene interactions. Direct comparison revealed that these techniques are more robust than existing methods in functional profiling of the yeast genome. Widespread application of these tools will elucidate a comprehensive yeast genetic network.

Gene Expression Profiling↗

PubMed2004

Pure component selectivity analysis of multivariate calibration models from near-infrared spectra.

A novel procedure is proposed as a method to characterize the chemical basis of selectivity for multivariate calibration models. This procedure involves submitting pure component spectra of both the target analyte and suspected interferences to the calibration model in question. The resulting model output is analyzed and interpreted in terms of the relative contribution of each component to the predicted analyte concentration. The utility of this method is illustrated by an analysis of calibration models for glucose, sucrose, and maltose. Near-infrared spectra are collected over the 5000-4000-cm(-)(1) spectral range for a set of ternary mixtures of these sugars. Partial least-squares (PLS) calibration models are generated for each component, and these models provide selective responses for the targeted analytes with standard errors of prediction ranging from 0.2 to 0.7 mM over the concentration range of 0.5-50 mM. The concept of the proposed pure component selectivity analysis is illustrated with these models. Results indicate that the net analyte signal is solely responsible for the selectivity of each individual model. Despite strong spectral overlap for these simple carbohydrates, calibration models based on the PLS algorithm provide sufficient selectivity to distinguish these commonly used sugars. The proposed procedure demonstrates conclusively that no component of the sucrose or maltose spectrum contributes to the selective measurement of glucose. Analogous conclusions are possible for the sucrose and maltose calibration models.

Calibration↗

PubMed2004

Adjustment of systematic microarray data biases.

MOTIVATION: Systematic differences due to experimental features of microarray experiments are present in most large microarray data sets. Many different experimental features can cause biases including different sources of RNA, different production lots of microarrays or different microarray platforms. These systematic effects present a substantial hurdle to the analysis of microarray data. RESULTS: We present here a new method for the identification and adjustment of systematic biases that are present within microarray data sets. Our approach is based on modern statistical discrimination methods and is shown to be very effective in removing systematic biases present in a previously published breast tumor cDNA microarray data set. The new method of 'Distance Weighted Discrimination (DWD)' is shown to be better than Support Vector Machines and Singular Value Decomposition for the adjustment of systematic microarray effects. In addition, it is shown to be of general use as a tool for the discrimination of systematic problems present in microarray data sets, including the merging of two breast tumor data sets completed on different microarray platforms. AVAILABILITY: Matlab software to perform DWD can be retrieved from https://genome.unc.edu/pubsup/dwd/

Algorithms↗

PubMed2004

Molecular classification of head and neck squamous cell carcinomas using patterns of gene expression.

The prognostication of head and neck squamous cell carcinoma (HNSCC) is largely based upon the tumor size and location and the presence of lymph node metastases. Here we show that gene expression patterns from 60 HNSCC samples assayed on cDNA microarrays allowed categorization of these tumors into four distinct subtypes. These subtypes showed statistically significant differences in recurrence-free survival and included a subtype with a possible EGFR-pathway signature, a mesenchymal-enriched subtype, a normal epithelium-like subtype, and a subtype with high levels of antioxidant enzymes. Supervised analyses to predict lymph node metastasis status were approximately 80% accurate when tumor subsite and pathological node status were considered simultaneously. This work represents an important step toward the identification of clinically significant biomarkers for HNSCC.

Adult↗

PubMed2004

[Rheological characteristic of microemulsion including phosphatidycholine].

This study aimed to evaluate the rheological characteristic of W/O microemulsion. Using the Low Shear-30 Sinus Rheometer, we assessed the effects of water percentage in microemulsion on the apparent viscosity of microemulsion at different shear rates and temperature, and on the viscoelasticity of microemulsion. The results demonstrated that with the increase of water, the apparent viscosities at four different shear rates increased exponentially. The fitted curve between water percentage and the apparent viscosity (eta) at low shear rate was steeper than the others. We found that viscous component (eta') and elastic component (eta") also increased exponentially when water percentage was increasing. This communication addressed the relationship between water percentage and eta, and discussed the physical meaning of the elastic component. The results suggest that both the viscous component and the elastic component present qualitatively physical nature, but the viscous component is more accurate than the other.

Chemical Phenomena↗

PubMed2004

[Molecular study on CisAB and B(A) blood group in Chinese individuals].

OBJECTIVE: This is a study on some ABO subgroup samples which show discordant results of serological and molecular blood typing, the aim is to clarify their true ABO type by means of nucleotide analysis on exons 6 and 7 of their ABO gene. METHODS: Absorb-elution test and family investigation were conducted to study 7 samples which were involved in ABO grouping discrepancies. Duplex polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) method was used to identify their ABO genotypes. PCR products of exons 6 and 7 were cloned and sequenced. RESULTS: All the 7 ABO subgroup samples with the discordant results of serological and molecular blood typing were found to have the normal O gene. Four out of them were typed as ABsub by serology, they were all of the A*102/O genotype. Sequencing analysis found all their A gene having the nt467 (C-->T) and nt803 (G-->C) mutation by comparison with the A*101 allele, i.e. their real type should be CisAB/O. Three out of 7 were typed as AsubB by serology and as BO by genotype; and point mutation was detected in all of their B gene. One of them had the nt700 (C-->G) mutation, the other 2 unrelated individuals had the novel nt640 (A-->G) mutation in their B alleles. CONCLUSION: Through nucleotide analysis, 7 samples have been typed as AB subgroup in serology with the normal O gene, their real ABO type being CisAB in 4 cases and B(A) in 3 cases. At the same time, a kind of novel B (A)640 allele has been uncovered in this study.

ABO Blood-Group System↗

PubMed2004

[Analysis on FUT1 and FUT2 gene of 10 para-Bombay individuals in China].

OBJECTIVE: This is a study on the allele composing of ABO, FUT1 and FUT2 gene loci of 10 para-Bombay individuals in China. METHODS: Ten samples coming from different districts of China were suspected of para-Bombay phenotype by primary serology tests. Routine and absorb-elution tests were conducted to identify their ABO type, and duplex polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was applied to getting their ABO genotype. Most of them were submitted to a test of their Lewis type as well. Then through direct DNA sequencing with PCR products of FUT1 and FUT2 genes, the genotypes of their H and SE gene loci were analyzed. RESULTS: It can be confirmed that the 10 samples are para-Bombay. All of their ABO genotypes are consistent with the serological absorb-elution results and the substances detected results in saliva. Seven out of 10 have recessive homozygous gene at their H locus. Each phenotype of h1h1 (nt547-552Deltaag), h2h2 (nt880-882Deltatt) and h4h4 (nt35 t-->c) are ascertained in 2 individuals; moreover, h3h3 (nt 658 c-->t) is identified in one individual. The rest are hh heterozygous individuals: one is h3/h(new-1); the other is h2/h(new-2); the last one is h1/h2. The h(new-1) (nt586 c-->t) allele has a point mutation at nt 586 C to T, which leads a nonsense mutation Gln(CAG) to stop (TAG).The second h (new-2) (nt328 g-->a) has an nt328 G to A missense mutation,which leads Ala (GCC),was replaced by Thr (ACC) at 110 amino acid position. All the 10 samples have Se (nt357 c-->t) synonymous mutation. One Bm(h) (B/O) individual with h4h4 phenotype has a Se(w)(nt357 c-->t; nt385 a-->t) allele, whose Lewis type is Le(a+b+). Moreover, the authors detected a (nt716 g-->a) mutation in two samples' Se gene. CONCLUSION: Four kinds of known h alleles (h1-h4), 2 kinds of novel non-functional FUT1 alleles, a Se(w) allele, and a novel SeG716A polymorphism in Chinese para-Bombay individuals were detected. At the same time, the authors noticed that all the 10 samples have the nt357 c-->t mutation in their FUT2 gene.

ABO Blood-Group System↗

PubMed2004

[Studies on the liver targeting of norcantharindin microemulsion].

AIM: To study the morphology, particle size distribution and biological reliability of the norcantharindin (NCTD)-loaded microemulsion and pharmacokinetics of the W/O norcantharidin-loaded microemulsion in mice. METHODS: The concentration of NCTD in plasma and tissues were determined by GC method. The data obtained were processed using 3P87 program. RESULTS: The mean particle diameter of microemulsion was (44 +/- 9) nm. The concentration-time curve of NCTD-loaded microemulsion and NCTD injection was fitted to a two-compartment model. At the same dosage, the pharmacokinetic study for NCTD-loaded microemulsion showed the NCTD microemulsion had relatively longer circulating time in mice. Area under the curve of concentration versus time (AUC), mean residence time (MRT) and half life (T1/2) for microemulsion and injection were (29.7 +/- 0.9) mg x h x L(-1), (9.25 +/- 0.09) mg x h x L(-1), (110 +/- 11) h, (86.7 +/- 0.8) h, (103 +/- 12) h, (42 +/- 4) h, respectively. Targeting index of NCTD microemulsion in liver and kidney in mice were 0.43 and 0.12 after iv NCTD-loaded microemulsion. The effects of biological reliability was not significantly different between NCTD microemulsion and NCTD injection in vivo and in vitro. CONCLUSION: The liver targeting absorptive capability of NCTD-loaded microemulsion was enhanced and the release time was extended compared with NCTD injection. While the microemulsion vehicles could decrease the kidney distribution of NCTD.

Animals↗