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27 results on '"Guan, Xiaomei"'

14. An Effective Segmentation Method for MRI Images Based on TV-L1 and GVF Model

Author

Xiaofei Li, Chaoying Yuan, Dongmei Wei, Xiaoxiao Pan, Weili Wang, Guan Xiaomei, and Yuefeng Zhao

Subjects
Liver surgery, Computer science, 02 engineering and technology, Theoretical Computer Science, 03 medical and health sciences, Mri image, 0302 clinical medicine, Wavelet, Robustness (computer science), 0202 electrical engineering, electronic engineering, information engineering, medicine, Segmentation, medicine.diagnostic_test, Vector flow, business.industry, Magnetic resonance imaging, Pattern recognition, Hardware and Architecture, Control and Systems Engineering, Modeling and Simulation, Signal Processing, 020201 artificial intelligence & image processing, Artificial intelligence, business, 030217 neurology & neurosurgery, Adaptive radiation therapy, Information Systems
Abstract

Liver magnetic resonance imaging (MRI) is of vital importance for computer-aided diagnosis and it is equally important in liver surgery planning. In this paper, accurate contours of the liver in MRI images automatically for subsequent adaptive radiation therapy can be extracted by the work. It is consisted of three components. Firstly, noise and artifacts are removed from the MRI image by an edge-preserving filtering using total variation with L1 norm (TV-L1). Secondly, the wavelet parameters are calculated at different levels of scale, and then the initial contour of the liver is obtained at the appropriate scale. And finally the precise liver structure is extracted by the gradient vector flow (GVF) model converging to the initial contour. The accuracy of the segmentation results are verified by comparing with the manually ones. For clinical cases, the numerical results illustrates enough accuracy and robustness for medical environments. And it also has a reasonable computational cost.

Published
2017

22. Nampt/Visfatin/PBEF: A Functionally Multi-faceted Protein with a Pivotal Role in Malignant Tumors

Author

He Jieyu, Guan Xiaomei, Li Mengjun, Wang Shalong, Tu Chao, Li Zhihong, and Lin Jianfeng

Subjects
Genome instability, Angiogenesis, medicine.medical_treatment, Antineoplastic Agents, Biology, medicine.disease_cause, Metastasis, Neoplasms, Drug Discovery, Biomarkers, Tumor, medicine, Animals, Humans, Molecular Targeted Therapy, Enzyme Inhibitors, Nicotinamide Phosphoribosyltransferase, Pharmacology, Cell growth, Growth factor, medicine.disease, Cytokine, Biochemistry, Cancer research, NAD+ kinase, Carcinogenesis, Signal Transduction
Abstract

Nampt/Visfatin/PBEF is a primary, rate-limiting enzyme involved in NAD+ biosynthesis, which serves as a pivotal substance for proteins, and is required for cell growth, survival, DNA replication and repair and energy metabolism. Growing researches have elucidated that it is a pleiotropic protein that functions not only as an enzyme, but also as an adipocytokin, a growth factor, and a cytokine. Additionally, accumulated evidences indicate that Nampt is correlated to various malignant tumors, and complicated mechanisms are proposed to be involved in the carcinogenesis, progression, invasion and metastasis of it, including regulation of energy metabolism and genome instability, promotion of proliferation, angiogenesis, and tumor-promoting inflammation, resistance in cell death and avoidance of immune destruction. APO866 and CHS-828 are recognized inhibitors of Nampt, known to block the intracellular and extracellular NAD+ synthesis pathway. Both of them are currently in clinical trials for the treatment of various malignant tumors and have been shown to represent novel promising antitumor chemotherapeutic agents.

Published
2012

24. Optimization of parthenogenetic activation of rabbit oocytes and development of rabbit embryo by somatic cell nuclear transfer.

Author

Zhang, Shun, Xiang, Shu, Yang, Jinji, Shi, Jinyue, Guan, Xiaomei, Jiang, Jianrong, Wei, Yingming, Luo, Chan, Shi, Deshun, and Lu, Fenghua

Subjects
RABBITS, OVUM, SOMATIC cell nuclear transfer, BLASTOCYST, ELECTROPORATION
Abstract

The present study explored a suitable parthenogenetic activation (PA) procedure for rabbit oocytes and investigated the developmental potential of somatic cell nuclear transfer (SCNT) embryos using rabbit foetal fibroblasts (RFFs). The electrical activation had the optimal rate of blastocyst (14.06%) when oocytes were activated by three direct current (DC) pulses (40 V/mm, 20 μs each) followed by 6‐dimethylaminopurine (6‐DMAP) and cycloheximide (CHX) treatment; the blastocyst rate of ionomycin (ION) + 6‐DMAP + CHX (12.07%) activation was higher than that of ION + 6‐DMAP (8.6%) activation or ION + CHX (1.24%) activation; there was no significant difference in blastocyst rate between ION + 6‐DMAP + CHX and DC + 6‐DMAP + CHX groups. The blastocyst rate of ION + 6‐DMAP + CHX‐activated oocytes in the basic rabbit culture medium (M‐199) + 10% foetal bovine serum (FBS; 14.28%) was higher than that in buffalo conditioned medium (5.75%) or G1/G2 medium (0), and the blastocyst rate was increased when M‐199 + 10% FBS was supplemented with amino acids. Refreshing culture medium every day or every other day significantly increased the blastocyst rate. Treatment of donor cells with 0.5% FBS for 3–5 days increased blastocyst rate of SCNT embryos (33.33%) than no serum starvation (22.47%) or 0.5% FBS treatment for 6–9 days (23.61%); the blastocyst rate of SCNT embryos derived from nontransgenic RFFs was higher than that derived from transgenic RFFs by electroporation. The blastocyst development ability of SCNT embryos derived from RFFs by electroporation (32.22%) was higher than that of liposome (19.11%) or calcium phosphate (20.00%) transfection, and only the embryos from electroporation group have the EGFP expression (24.44%). In conclusion, this study for the first time systematically optimized the conditions for yield of rabbit embryo by SCNT. [ABSTRACT FROM AUTHOR]

Published
2019
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27. Efficient generation ofsFat-1transgenic rabbits rich in n-3 polyunsaturated fatty acids by intracytoplasmic sperm injection.

Author

Zhang, Shun, Lu, Fenghua, Liu, Qingyou, Liu, Yubing, Guan, Xiaomei, Wei, Yingming, Tan, Shijian, and Shi, Deshun

Subjects
TRANSGENIC animals, RABBIT reproduction, UNSATURATED fatty acids, INTRACYTOPLASMIC sperm injection, FERTILIZATION in vitro
Abstract

N-3 polyunsaturated fatty acids (n-3 PUFAs) have their first double bond at the third carbon from the methyl end of the fatty-acid chain and had been proven to be beneficial to human health. However, mammals cannot produce n-3 PUFAs by themselves because they lack the n-3 fatty-acid desaturase (Fat-1) gene. Thus, the possibility of producing sFat-1 transgenic rabbits was explored in this study. The transgenic cassette of pPGK1–sFat-1–CMV–EGFP was constructed and transgenic rabbit embryos were produced by intracytoplasmic sperm injection (ICSI). When 123 EGFP-positive embryos at the 2–8-cell stage were transplanted into the oviduct of four oestrous-synchronised recipients, two of them became pregnant and gave birth to seven pups. However, transfer of embryos into the uterus of oestrous-synchronised recipients and oviduct or uterus of oocyte donor rabbits did not result in pregnancy. The integration of the sFat-1 gene was confirmed in six of the seven live pups by PCR and Southern blot. The expression of the sFat-1 gene in the six transgenic pups was also detected by reverse transcription polymerase chain reaction (RT-PCR). Gas chromatography–mass spectrometry analysis revealed that transgenic rabbits exhibited an ~15-fold decrease in the ratio of n-6:n-3 PUFAs in muscle compared with wild-type rabbits and non-transgenic rabbits. These results demonstrate that sFat-1 transgenic rabbits can be produced by ICSI and display a low ratio of n-6:n-3 PUFAs. [ABSTRACT FROM AUTHOR]

Published
2016
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