Biomedical subjects

Xiao-Hui Ma

Publications and source records attributed to Xiao-Hui Ma.

4 recordsLinked to original sources

PubMed2005

Differential responses of visceral and subcutaneous fat depots to nutrients.

Increased visceral adiposity is a pivotal component of the metabolic syndrome. Differential gene expression patterns of fat-derived peptides (FDPs) in visceral fat and subcutaneous fat have been characterized in the fasting state. Here we examined whether delivery of nutrients differentially affects the expression of FDPs in visceral fat versus subcutaneous fat (in the fed state). We increased the rate of glucose flux into adipose tissue of normal rats (n = 16) by hyperglycemia or hyperinsulinemia using the clamp technique. Glucose uptake was associated with increased expression of FDPs, including resistin ( approximately 5-fold), adiponectin ( approximately 2-fold), leptin ( approximately 15-fold), plasminogen activating inhibitor-1 ( approximately 10-fold), and angiotensinogen ( approximately 4-fold) in visceral fat, but markedly less in subcutaneous fat. Cytokine expression derived mainly from vascular/stromal/macrophage components of adipose tissue was less dramatically increased. Infusion of glucosamine amplified the results obtained by increasing glucose uptake into adipose tissue, suggesting that flux through the hexosamine biosynthetic pathway may serve as a mechanism for "nutrient sensing." Nutrient-dependent expression of FDPs in visceral fat was also associated with increased plasma levels of several FDPs. Because a biologic sensing pathway can dynamically couple daily food intake to abnormal plasma levels of important FDPs, we challenge the practice of obtaining plasma levels after fasting to assess risk factors for metabolic syndrome.

Adipose Tissue↗

PubMed2003

A soft docking algorithm for predicting the structures of protein-protein complexes.

An efficient soft docking algorithm is described to predict the mode of binding between two proteins based on the three-dimensional structures of molecules. The molecular model used in this work was grounded on the "simplified protein" model used in Janin's docking algorithm. The side chain flexibility of the amino acid residues Arg, Lys, Asp, Glu and Met at the protein surface was considered through softening the molecular surface. A double filtering technique was used to eliminate most of the unlike binding modes. The energy minimization was performed on the retained structures, and then these structures were evaluated with the scoring function which included electrostatic, desolvation and van der Waals energy terms. The 26 complexes were used to test this docking algorithm and good results were obtained. The native-like conformations of all the complexes were all found, of which 20 were ranked in the top 10.

Algorithms↗

PubMed2003

[The application of SCGE-KIAS in monitoring of DNA damage in lymphocytes of tumor patients treated with cyclophosphamide].

Single cell gel electrophoresis assay (SCGE), also named as alkaline comet assay, was a simple, rapid and sensitive method to evaluate DNA damage. In this study SCGE technique was used to monitor DNA damage difference in tumor patients caused by chemotherapy, DNA damage distribution frequency and DNA damage characters were analyzed by komet image analysis system (KIAS). The results showed that cyclophosphamide greatly caused DNA damage in lymphocytes of tumor patients. There was significant difference of peripheral blood lymphocyte DNA damage between tumor patients and healthy controls. Tail length of lymphocytes were 33.69 +/- 7.56 micro m, and tail DNA% we re 31.51 +/- 5.4 6% in 10 cancer patients treated with cyclophosphamide, while Tail length were 1 6.2 +/- 1.5 micro m and tail DNA% were 7.46 +/- 1.15% in healthy controls. there was great significant difference on tail length and tail DNA% values between cancer patients and healthy controls (P < 0.01). In conclusion, the successful measurement of DNA damage caused by Cyclophosphamide treatment means that the alkaline comet assay as a valuable tool can be very useful in cancer epideminology study, and also be valuable to evaluate DNA damage status of patients in clinic.

Comet Assay↗

PubMed2003

[Relationship between stenosis of left anterior descending artery and left internal mammary artery blood flow].

OBJECTIVE: To compare the blood flow of left internal mammary artery (LIMA) anastomosed to left anterior descending artery (LAD) with variable degree of stenosis in off pump coronary artery bypass grafting (OPCAB). METHODS: From 2000.9 to 2002.12, 167 cases (from a total of 209 OPCAB) were involved in this study. According to the degree of stenosis of LAD, all the cases were divided into group A (< 75%), group B (75% approximately 95%) and group C (> 95%). Blood flow of LIMA, routinely anatomized to LAD was immediately measured after anastomosis with transit-time flowmeter (TTFM) and several parameters were recorded. RESULTS: The mean blood pressure at measurement was not significantly different (P = 0.08). Mean blood flow of group A (11.1 +/- 1.2) ml/min, B (16.3 +/- 1.6) ml/min and C (28.3 +/- 3.2) ml/min and diastolic flow of group A (26.3 +/- 2.8) ml/min, group B (34.8 +/- 3.2) ml/min and group C (55.1 +/- 5.3) ml/min, were significantly different between every two groups (P < 0.01) and the latter was bigger than the former. Systolic blood flow among group A (5.3 +/- 0.7) ml/min, group B (4.3 +/- 1.4) ml/min and group C (4.6 +/- 1.3) ml/min were not different (P = 0.91). Pulsatility index (PI) of group C (2.75 +/- 0.14) was significantly smaller than that of group A (4.36 +/- 0.47) and group B (3.72 +/- 0.31) (P < 0.01), but PI between groups A and B was of no significant difference (P = 0.12). CONCLUSION: Mean and diastolic blood flow of LIMA were closely related to the degree of stenosis of LAD. The higher the degree, the bigger the blood flow, and the smaller the value of PI. However, systolic blood flow was not influenced by the degree of lesion.

Adult↗