Biomedical subjects

Xuemei Guo

Publications and source records attributed to Xuemei Guo.

3 recordsLinked to original sources

PubMed2005

Asymmetry analysis of cingulum based on scale-invariant parameterization by diffusion tensor imaging.

Current analysis of diffusion tensor imaging (DTI) is based mostly on a region of interest (ROI) in an image dataset, which is specified by users. This method is not always reliable, however, because of the uncertainty of manual specification. We introduce an improved fiber-based scheme rather than an ROI-based analysis to study in DTI datasets of 31 normal subjects the asymmetry of the cingulum, which is one of the most prominent white matter fiber tracts of the limbic system. The present method can automatically extract the quantitative anisotropy properties along the cingulum bundles from tractography. Moreover, statistical analysis was carried out after anatomic correspondence specific to the cingulum across subjects was established, rather than the traditional whole-brain registration. The main merit of our method compared to existing counterparts is that to find such anatomic correspondence in cingulum, a scale-invariant parameterization method by arc-angle was proposed. It can give a continuous and exact description on any segment of cingulum. More interestingly, a significant left-greater-than-right asymmetry pattern was obtained in most segments of cingulum bundle (-50-25 degrees), except in the most posterior portion of cingulum (25-50 degrees).

Adult↗

PubMed2003

Rab27b is associated with fusiform vesicles and may be involved in targeting uroplakins to urothelial apical membranes.

The terminally differentiated umbrella cells of bladder epithelium contain unique cytoplasmic organelles, the fusiform vesicles, which deliver preassembled crystalline arrays of uroplakin proteins to the apical cell surface of urothelial umbrella cells. We have investigated the possible role of Rab proteins in this delivery process, and found Rab27b to be expressed at an extraordinary high level (0.1% of total protein) in urothelium, whereas Rab27b levels were greatly reduced (to <5% of normal urothelium) in cultured urothelial cells, which synthesized only small amounts of uroplakins and failed to form fusiform vesicles. Immuno-electron microscopy showed that Rab27b was associated with the cytoplasmic face of the fusiform vesicles, but not with that of the apical plasma membrane. The association of Rab27b with fusiform vesicles and its differentiation-dependent expression suggest that this Rab protein plays a role in regulating the delivery of fusiform vesicles to the apical plasma membrane of umbrella cells.

Animals↗

PubMed2002

[Molecular analysis of two pedigrees with hereditary F VII deficiency].

OBJECTIVE: To identify the mutation of coagulation factor VII (F VII) gene in two pedigrees with hereditary F VII deficiency. METHODS: F VII gene mutations were analysed in two propositi and their family members by direct DNA sequencing. Allele specific PCR and PCR combined with restricted enzyme digestion were used to confirm the detected mutations. RESULTS: Two gene mutations were detected in the propositus of pedigree A: G to C transition at position 6390 resulting in Trp40Cys and G to A at 11496 resulting in Arg353Gln, both are heterozygotes. The heterozygosity for polymorphism Arg353Gln was confirmed with the restriction enzyme Msp I digestion in his mother. In the propositus of pedigree B, there was a T to G transition at position 11482 resulting in His348Gln, heterozygosity of which was confirmed with Nsp I digestion in the propositus and his daughter. G to T transition at position 11514 resulting in Thr359Met was also found in the propositus of pedigree B, and the heterozygosity for Thr359Met was confirmed with allele specific PCR in the propositus and his son. CONCLUSION: Three missense mutations were found in two pedigrees with hereditary F VII deficiency. A novel Trp40Cys mutation was reported for the first time.

Factor VII↗