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Biomedical subjects

Qi Liang

Publications and source records attributed to Qi Liang.

8 recordsLinked to original sources
PubMed2005

Ultrasound-accelerated tissue fixation/processing achieves superior morphology and macromolecule integrity with storage stability.

We demonstrate that high-frequency and high-intensity ultrasound (US) can be applied to both tissue fixation and tissue processing to complete the conventional overnight formalin-fixation and paraffin-embedding (FFPE) procedures within 1 hr. US-facilitated FFPE retains superior tissue morphology and long-term room temperature storage stability than conventional FFPE. There is less alteration of protein antigenicity after US-FFPE preservation so that rapid immunohistochemical reactions occur with higher sensitivity and intensity, reducing the need for antigen retrieval pretreatment. US-FFPE tissues present storage stability so that room temperature storage up to 7 years does not significantly affect tissue morphology, protein antigenic properties, RNA distribution, localization, and quantitation. In addition, during fixation, tissue displays physical changes that can be monitored and reflected as changes in transmission US signals. As far as we know, this is the first effort to monitor tissue physical changes during fixation. Further study of this phenomenon may provide a method to control and to monitor the level of fixation for quality controls. The mechanism of less alteration of protein antigenicity by US-FFPE was discussed.

Autopsy↗
PubMed2005

[Expressions of aquaporin-1 on peritonea in hepatic cirrhotic rats with ascites].

OBJECTIVE: To investigate the changes of aquaporin (AQP-1) expressions on peritonea in liver cirrhotic rats with ascites, and to study the correlation between AQP-1 expressions and ascites form. METHODS: 32 healthy Sprague-Dawley (SD) rats were divided into two groups randomly, 20 rats were used to produce liver cirrhotic models induced with phenobarbitol sodium and CCl(4). The distribution and protein expressions of AQP-1 on the rats' peritonea were measured with immunohistochemistry assay, and the expressions of APQ-1 mRNA were tested with relative GAPDH quantitative RT-PCR. RESULTS: (1) The expressions of AQP-1 were mainly on the endothelial cells of capillary vessels and venules on the rats' peritonea, and also on mesothelial cells. (2) There was no statistically significant difference between the expressions of AQP-1 protein and mRNA in the two groups on the early stage of liver cirrhosis. (3) Downregulations of the expressions of AQP-1 protein and mRNA were observed in B group on the advanced cirrhotic stage. CONCLUSION: Expressions of AQP-1 were downregulated on the peritonea of rats with decompensated liver cirrhosis, which may play a role in the formation of ascites. The changes of AQP-1 Expressions on peritoneal mesothelial cells which were fewer than those on the endothelial cells may be few relations to ascites form.

Animals↗
PubMed2005

Gene expression profile in rat small intestinal allografts after cold preservation/reperfusion.

AIM: To determine the changes of gene expression profile in small intestinal allografts in rats after cold preservation/reperfusion, and to identify the genes relevant to cold preservation/reperfusion injury. METHODS: Heterotopic segmental small bowel transplantation was performed in six rats with a sham operation and they were used as controls. Total RNA was extracted from the allografts (experimental group) and normal intestines (control group) 1 h after cold preservation/reperfusion, and then purified to mRNA, which was then reversely transcribed to cDNA, and labeled with fluorescent Cy5-dUTP and Cy3-dUTP to prepare hybridization probes. The mixed probes were hybridized to the cDNA microarray. After high-stringent washing, the fluorescent signals on cDNA microarray chip were scanned and analyzed. RESULTS: Among the 4 096 target genes, 82 differentially expressed genes were identified between the two groups. There were 18 novel genes, 33 expression sequence tags, and 31 previously reported genes. The selected genes may be divided into four classes: genes modulating cellular adhesion, genes regulating cellular energy, glucose and protein metabolism, early response genes and other genes. CONCLUSION: A total of 82 genes that may be relevant to cold preservation/reperfusion injury in small intestinal allografts are identified. Abnormal adhesion between polymorphonuclears and endothelia and failure in energy, glucose and protein metabolism of the grafts may contribute to preservation/reperfusion injury. The functions of the novel genes identified in our study need to be clarified further.

Animals↗
PubMed2005

A nondestructive molecule extraction method allowing morphological and molecular analyses using a single tissue section.

In clinical practice, molecular analysis of tumor specimens is often restricted by available technology for sample preparation. Virtually all current methods require homogenization of tissues for molecule extraction. We have developed a simple, rapid, nondestructive molecule extraction (NDME) method to extract proteins and nucleic acids directly from a single fixed or frozen tissue section without destroying the tissue morphology. The NDME method is based upon exposure of micron-thick tissue section to extraction buffer with the help of heating and/or intact physical forces (ultrasound and microwave) to facilitate release of macromolecules into the buffer. The extracted proteins and nucleic acids can be used directly without further purification for downstream SDS-PAGE analysis, immunoblotting, protein array, mass spectra protein profiling, PCR, and RT-PCR reactions. Most importantly, the NDME procedure also serves as an antigen retrieval treatment, so that after NDME, the same tissue section can be used for histopathological analyses, such as H&E staining, immunohistochemistry, and in situ hybridization. Thus, the NDME method allows, for the first time, both histological diagnosis and molecular analysis on a single tissue section, whether it is from frozen or fixed tissue specimens.

Animals↗
PubMed2005

Ultrasound-accelerated formalin fixation of tissue improves morphology, antigen and mRNA preservation.

Formalin fixation and paraffin embedding are conventional tissue preservation and processing methods used for histologic diagnosis in over 90% of cases. However, formalin fixation has three disadvantages: (1) slow fixation (16-24 h) hinders intraoperative decision making, (2) slow quenching of enzymatic activity causes RNA degradation, and (3) extensive molecule modification affects protein antigenicity. Applying high-frequency, high-intensity ultrasound to the formalin fixative cuts fixation time to 5-15 min. Fixation of various tissues such as lymph node, brain, breast, and prostate suggests that, compared to the conventional method, implementation of ultrasound retains superior and more uniform tissue morphology preservation. Less protein antigenicity is altered so that rapid immunohistochemical reactions occur with higher sensitivity and intensity, reducing the need for antigen retrieval pretreatment. Better RNA preservation results in stronger signals in in situ hybridization and longer RNA fragments extracted from fixed tissues, probably due to rapid inhibition of endogenous RNase activity. Molecules extracted from ultrasound-fixed tissues are of greater integrity and quantity compared to conventionally fixed tissues, and thus better support downstream molecular analyses. Overall, ultrasound-facilitated tissue preservation can provide rapid and improved morphological and molecular preservation to better accommodate both traditional and molecular diagnoses.

Antigens↗
PubMed2003

Effect of C60 molecular rotation on nanotribology.

The effect of C60 molecular rotation on the nanotribological properties of C60 single crystal surfaces has been studied by atomic/frictional force microscopy. The orientational order-disorder phase transition, in which the high temperature C60 free rotation is reduced to a low temperature hindered rotation, is shown to give rise to an abrupt change in friction and adhesion. This change in frictional force is quantitatively consistent with the observed change in adhesion. The similar slopes of the friction versus load curves in both phases indicate that the friction coefficient in the two phases remains about the same. Hence the C60 rotation does not provide an additional energy dissipation channel in the friction process.

Journal Article↗
PubMed2002

Molecular testing for hereditary hemochromatosis.

Recent molecular genetic testing methods for hereditary hemochromatosis (HH) and single nucleotide polymorphisms are summarized. Comparisons of various sample preparation and detection instrumentation are made in terms of automation, cost, high-throughput and feasibility of implementation in a clinical laboratory. Examples are given for the analysis of the two mutations associated with hereditary hemochromatosis (HH) by high-performance liquid chromatography, capillary electrophoresis and mass spectrometry based on single nucleotide extension. The trends for developing better genetic testing are discussed.

Genetic Testing↗