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Biomedical subjects

Mei Han

Publications and source records attributed to Mei Han.

At least 55 records · Page 3Linked to original sources
PubMed2004

[Application of genomics and proteomics in study of traditional Chinese medicine].

The technique of genomics and proteomics is one of the fastest developments with the farest-reaching consequences in the high and new biotechnology in the world of today. It can be used to screen the target molecules of the action of traditional Chinese medicines, to identify the new effective components from traditional Chinese medicines, and to explore the mechanisms of the effects of traditional Chinese medicines. It meets the shortcomings of the conventional methodology being applied in the current studies of traditional Chinese medicine. Application of the theories and technique of genomics and proteomics in the study of traditional Chinese medicine would be of great significance for opening new research field of traditional Chinese medicine, for facilitating the integration of traditional Chinese medicine and modern biological science and technology, and for promoting the internationalization of traditional Chinese medicine.

Drug Delivery Systems↗
PubMed2004

[Effect of yiqi huoxue huayu recipe on vascular collagen turnover and relevant gene expression].

OBJECTIVE: To explore the effect of Yiqi Huoxue recipe (YHR), a Chinese herbal medicine for supplementing Qi, activating blood circulation to remove stasis, on vascular extracellular matrix (ECM) remodeling and its molecular mechanism. METHODS: Vascular smooth muscle cell (VSMC) proliferation activity and collagen turnover rate were detected by 3H-TdR test and hydroxyproline amount determined by 3H-Pro incorporation. Expression activity of MMP-2 and osteopontin genes was detected by Northern blotting and MMP-2 zymography analysis. RESULTS: YHR could markedly inhibit VSMC collagen synthesis stimulated by blasic fibroblast growth factor (bFGF) and lower the collagen turnover rate induced by vascular de-endothelialization. The expression level of MMP-2 and osteopontin genes was down-regulated by YHR in cultured VSMC and vascular wall with endothelial injury, and VSMC proliferation was inhibited by the serum obtained from YHR treated rats. Removing protein from the drug serum made no change on the effect of YHR to VSMC. CONCLUSION: YHR could inhibit and/or retard ECM remodeling through regulating the expression of MMP-2 and osteopontin genes and lowering the collagen turnover rate.

Animals↗
PubMed2004

[Expression of thymidine phosphorylase in human colorectal carcinoma and its clinical significance].

BACKGROUND & OBJECTIVE: Angiogenesis has been well known to be a factor related to the tumor growth and metastasis. Recent studies have reported that thymidine phosphorylase (TP) is identical with platelet-derived endothelial cell growth factor. It not only plays a role in the induction of the tumor angiogenesis, but also enhances the chemotherapeutical sensitivity of the tumor cells to prodrug of 5-fluorouracil. However, until now, the complete identity of view about the function of TP expression in colorectal carcinoma and its prognostic significance has not been reached. The present study was to explore the TP expression level in human colorectal carcinoma and its clinical significance. METHODS: Seventy archived samples of the patients with colorectal carcinoma were detected by immunohistochemical staining. These patients had undergone radical surgical treatment at the First Hospital of Xi'an Jiaotong University and had been followed up for 5 years after operation. RESULTS: TP expression was predominantly observed in the cytoplasm of the tumor cells. The positive rate was 57.14%(40/70). TP expression levels in the patients with different Dukes, stages and histopathological grades showed obvious difference (P=0.007 and 0.002, respectively). By Kaplan-Meier methods, the survival of TP positive expression group was shorter than that of TP negative expression group, and the five-year survival rates of TP positive expression group and TP negative expression group were 33.33% and 73.33% (P=0.000). The results indicated that the prognosis of the patients with TP positive expression was poorer than that of patients with TP negative expression. CONCLUSION: These findings suggest that TP expression might be one of the important prognostic indicators for colorectal carcinoma patients, and TP detection in colorectal carcinoma patients might served as a parameter for designing therapeutic schedule and choosing prodrug of 5-fluorouracil.

5'-Nucleotidase↗
PubMed2004

[Treatment of Bell's palsy with combination of traditional Chinese medicine and western medicine].

OBJECTIVE: To evaluation the clinical effect of combination of traditional Chinese medicine and western medicine on Bell's palsy. METHODS: 83 patients with Bell's palsy were randomly divided into two groups (trail group 54 cases and control group 29 cases). Patients in two groups were treated with medicine, acupuncture, physiotherapy, while patients in the trail group were treated with massage and functional exercise as the same time. The results of both groups were evaluated according to Portmann's Simple Scale. RESULTS: The score before treatment of trail group was 2.907 +/- 1.794, while control group was 2.931 +/- 2.034. And the score after treatment of trail group was 18.593 +/- 1.743, while control group was 9.862 +/- 3.091. Score of the function of facial muscles obtained from trail group was distinctly higher than that was from the control group (P < 0.01), as well as the improvement index (P < 0.01, trail group: 0.844 +/- 0.095, control group: 0.712 +/- 0.129). CONCLUSION: There is significant curative effect and suitability in the treatment of Bell's palsy with combination of traditional Chinese medicine and western medicine. The improvement of facial muscles' motive function pre- and post-treatment and quantitative evaluation of curative effect can be objectively obtained by evaluation of facial muscles' function.

Acupuncture Therapy↗
PubMed2004

[Isolation, culture and multipotent differentiation of mesenchymal stem cells from human fetal livers].

OBJECTIVE: To isolate and culture mesenchymal stem cells (MSCs) from human fetal livers and describe their biological characteristics. METHODS: MSCs were acquired using an optimized method. Cell cycles and the immunophenotype of the cells were analyzed by flow cytometry. The osteogenic and adipogenic differentiations were induced and identified by specific stainings, and hepatic differentiation by morphology and RT-PCR. RESULTS: The target cells derived from human fetal livers adhered to the plate with fibroblast-like morphology, whose surface markers were CD90, CD44, CD147 positive, and CD34, CD45, HLA-DR negtive. In the differentiation study, these cells could be induced to differentiate into osteogenic, adipogenic and hepatocyte-like cells. CONCLUSION: Multipotent MSCs can be isolated and cultured from human fetal livers.

Cell Differentiation↗
PubMed2004

[Effects of Astragalus and saponins of Panax notoginseng on MMP-9 in patients with type 2 diabetic macroangiopathy].

OBJECTIVE: To investigate the role and mechanism of Astragalus (AS) and saponins of Panax notoginseng (PNS) in treating type 2 diabetic macroangiopathy. METHOD: 94 patients with type 2 diabetic macroangiopathy were divided into two groups randomly: group treated with Simvastatin and group treated with AS and PNS, compared with 40 healthy control subjects. Serum level of MMP-9 and lipid in patients and healthy subjects were measured before and after treatment. RESULT: The serum levels of MMP-9, TG, TC, LDL-C, VLDL-C in patients with type 2 diabetic macroangiopathy were improved, while the levels of HDL-C were decreased. Like Simvastatin AS and PNS had the function of reducing MMP-9 and accommodating lipid metabolism. CONCLUSION: Besides accommodating lipid metabolism, AS and PNS can also reduce the level of serum MMP-9 soas to treat type 2 diabetic macroangiopathy.

Aged↗
PubMed2003

Expression profiling and identification of novel genes involved in myogenic differentiation.

Skeletal muscle differentiation is a complex, highly coordinated process that relies on precise temporal gene expression patterns. To better understand this cascade of transcriptional events, we used expression profiling to analyze gene expression in a 12-day time course of differentiating C2C12 myoblasts. Cluster analysis specific for time-ordered microarray experiments classified 2895 genes and ESTs with variable expression levels between proliferating and differentiating cells into 22 clusters with distinct expression patterns during myogenesis. Expression patterns for several known and novel genes were independently confirmed by real-time quantitative RT-PCR and/or Western blotting and immunofluorescence. MyoD and MEF family members exhibited unique expression kinetics that were highly coordinated with cell-cycle withdrawal regulators. Among genes with peak expression levels during cell cycle withdrawal were Vcam1, Itgb3, Itga5, Vcl, as well as Ptger4, a gene not previously associated with the process of myogenesis. One interesting uncharacterized transcript that is highly induced during myogenesis encodes several immunoglobulin repeats with sequence similarity to titin, a large sarcomeric protein. These data sets identify many additional uncharacterized transcripts that may play important functions in muscle cell proliferation and differentiation and provide a baseline for comparison with C2C12 cells expressing various mutant genes involved in myopathic disorders.

Animals↗
PubMed2003

Altered levels of POMC, AgRP and MC4-R mRNA expression in the hypothalamus and other parts of the limbic system of mice prone or resistant to chronic high-energy diet-induced obesity.

The melanocortinergic system plays an important role in promoting negative energy balance and preventing excessive fat deposition. This study has investigated the levels of mRNA expression of proopiomelanocortin (POMC), agouti-related protein (AgRP) and the melanocortin-4 receptor (MC4-R) in diet-induced obese (DIO) and diet-resistant (DR) mice. Thirty C57 mice were used in this study. Twenty-four mice were fed with a high-fat diet (HF: 40% of calories from fat, 20% from saturated fat) for 4 weeks and then classified as DIO and DR according to their body weight gain. Six mice were placed on a low-fat diet (LF: 10% of calories from fat, 1% from saturated fat) and were used as controls. After 22 weeks of feeding, visceral fat deposits were more than twice as heavy in the DIO mice as in the DR and LF mice, while the latter two groups had no significant difference. Using quantitative in situ hybridization techniques, this study found that the DIO mice had a significantly lower level of Arc POMC (-29%) and AgRP (-31%) mRNA expression than the DR and LF mice, respectively. The mice on high-fat diets had higher levels of AgRP mRNA expression in the bed nucleus of stria terminalis (BST), and ventral part of the lateral septal nucleus (LSV) than the LF mice. Furthermore, the DIO mice had a 40% higher level of MC4-R mRNA expression in the ventromedial hypothalamic nucleus (VMH) and posterodorsal part of the medial amygdaloid nucleus (MePD) than the LF mice. In conclusion, this study has demonstrated that differential expression of POMC, AgRP and MC4-R mRNA levels exists in DIO, DR and LF mice. These differences were shown to occur in the specific nuclei of the hypothalamus and other parts of the limbic system. These findings may assist in understanding the involvement of the melanocortinergic system in the regulation of body weight via the autonomic and limbic systems.

Agouti-Related Protein↗
PubMed2003

T cell recognition of distinct peptide:I-Au conformers in murine experimental autoimmune encephalomyelitis.

We have used T cells bearing TCRs that are closely related in sequence as probes to detect conformational variants of peptide-MHC complexes in murine experimental autoimmune encephalomyelitis in H-2(u) mice. The N-terminal epitope of myelin basic protein (MBP) is immunodominant in this model. Our studies have primarily focused on T cell recognition of a position 4 analog of this peptide (MBP1-9[4Y]) complexed with I-A(u). Using site-directed mutagenesis, we have mapped the functionally important complementarity determining region residues of the 1934.4 TCR Valpha domain. One of the resulting mutants (Tyr(95) to alanine in CDR3alpha, Y95A) has interesting properties: relative to the parent wild-type TCR, this mutant poorly recognizes Ag complexes generated by pulsing professional APCs (PL-8 cells) with MBP1-9[4Y] while retaining recognition of MBP1-9[4Y]-pulsed unconventional APCs or insect cell-expressed complexes of I-A(u) containing tethered MBP1-9[4Y]. Insect cell expression of recombinant I-A(u) with covalently tethered class II-associated invariant chain peptide or other peptides which bind relatively weakly, followed by proteolytic cleavage of the peptide linker and replacement by MBP1-9[4Y] in vitro, results in complexes that resemble peptide-pulsed PL-8 cells. Therefore, the distinct conformers can be produced in recombinant form. T cells that can distinguish these two conformers can also be generated by the immunization of H-2(u) mice, indicating that differential recognition of the conformers is observed for responding T cells in vivo. These studies have relevance to understanding the molecular details of T cell recognition in murine experimental autoimmune encephalomyelitis. They are also of particular importance for the effective use of multimeric peptide-MHC complexes to characterize the properties of Ag-specific T cells.

Amino Acid Substitution↗
PubMed2003

The level of NPY receptor mRNA expression in diet-induced obese and resistant mice.

Some mice become obese whereas others remain lean when raised on a high-energy diet. This study examined the levels of neuropeptide Y (NPY), and of Y1, Y2, Y5 and leptin receptor mRNA expression in the hypothalamic arcuate nucleus (Arc) of chronic high-energy diet-induced obese (DIO) and resistant (DR) mice. Forty mice were divided into two groups and fed either a high-fat (HF: 40% of calories from fat, 20% of calories from saturated fat; n=34) or low-fat (LF: 10% of calories from fat, 1% from saturated fat; n=6) diet. After 22 weeks of feeding, visceral fat accumulation was 69% higher in DIO mice compared with DR mice, and the former showed a moderate level of glucose intolerance. In DIO mice, the levels of NPY and leptin receptor mRNA expressions were significantly higher than in LF mice (+32 and +14%, P<0.001 and 0.05 respectively), indicating central leptin resistance, whereas the DR and LF groups did not differ. The level of Y2 receptor mRNA expression was similar between the DIO and LF groups but, importantly, was reduced approximately 20% in DR mice (P<0.005). The level of Y5 receptor mRNA was 36% lower in DR mice than DIO mice (P<0.05). The differences between DIO and DR mice identified by this study may assist in a better understanding of genetic predisposition to an increased fat deposition induced by a chronic high-fat diet. A low level of Y2 and Y5 receptor mRNA expression may contribute to the prevention of chronic high-energy diet-induced obesity in DR mice.

Adipose Tissue↗
PubMed2003

[Preparation and biological activities of monoclonal antibody against p185erbB2].

OBJECTIVE: To produce anti- p185erbB2 monoclonal antibody and investigate its biological activities on cancer cells that overexpress p185erbB2. METHODS: BALB/c mice were immunized with NIH3T3-erbB2 cell to prepare the anti- p185erbB2 monoclonal antibody. The specificity of the monoclonal antibody 1H3 was identified with ELISA, Western blot, immunoprecipitation and immunohistochemistry assays. The effects of monoclonal antibody 1H3 on the proliferation of cell lines that overexpressed p185erbB2 were measured by MTT assay. RESULTS: One strain of monoclonal antibody1H3 was obtained. In ELISA assay, 1H3 specifically reacted with cells overexpressing p185erbB2, but had no reaction with cells not overexpressing p185erbB2. The specificity of the monoclonal antibody 1H3 was verified by immunoprecipitation, Western blot and immunohistochemistry techniques. MTT assay was used to confirm that 1H3 could inhibit the growth of cells that overexpressed p185erbB2 to different extent. CONCLUSION: The monoclonal antibody 1H3 obtained can specifically bind to p185erbB2 and significantly inhibit proliferation of cells overexpressing p185erbB2.

Animals↗
PubMed2003

Gene expression profiling of Duchenne muscular dystrophy skeletal muscle.

The primary cause of Duchenne muscular dystrophy (DMD) is a mutation in the dystrophin gene, leading to absence of the corresponding protein, disruption of the dystrophin-associated protein complex, and substantial changes in skeletal muscle pathology. Although the primary defect is known and the histological pathology well documented, the underlying molecular pathways remain in question. To clarify these pathways, we used expression microarrays to compare individual gene expression profiles for skeletal muscle biopsies from DMD patients and unaffected controls. We have previously published expression data for the 12,500 known genes and full-length expressed sequence tags (ESTs) on the Affymetrix HG-U95Av2 chips. Here we present comparative expression analysis of the 50,000 EST clusters represented on the remainder of the Affymetrix HG-U95 set. Individual expression profiles were generated for biopsies from 10 DMD patients and 10 unaffected control patients. Two methods of statistical analysis were used to interpret the resulting data (t-test analysis to determine the statistical significance of differential expression and geometric fold change analysis to determine the extent of differential expression). These analyses identified 183 probe sets (59 of which represent known genes) that differ significantly in expression level between unaffected and disease muscle. This study adds to our knowledge of the molecular pathways that are altered in the dystrophic state. In particular, it suggests that signaling pathways might be substantially involved in the disease process. It also highlights a large number of unknown genes whose expression is altered and whose identity therefore becomes important in understanding the pathogenesis of muscular dystrophy.

Biopsy↗
PubMed2003

Multiplex single nucleotide extension: a robust and high throughput method for HLA-A locus typing.

This report describes a typing method that can identify all known human leukocyte antigen A (HLA-A) alleles by determining nucleotides present at polymorphic sites using single nucleotide extension. Allele specific primers are bound to capture oligonucleotides which allows for a multiplex approach during single nucleotide extension (SNE) reactions. Eleven group-specific polymerase chain reaction amplifications were performed to obtain the templates to be analyzed with sets of primers designed to investigate the polymorphisms. Extension of biotin-labeled ddNTPs onto allele-specific primers was catalyzed by a DNA polymerase and each primer was hybridized to a specific capture oligonucleotide covalently bound to a bead. After staining with streptavidin-PE, incorporated fluorescence was determined with a flow cytometer. Fluorescence intensities were interpreted by computer and the nucleotide sequence was translated into HLA-A genotypes. Group-specific amplification reactions and primer sets for SNE were validated with 42 reference samples of known HLA-A alleles. In addition, 296 samples from three populations (N. A. Caucasian, African-American, Terena S. A. Indian) were analyzed and results compared to previous typing by SSOP. Reproducibility between repeated typings was 100% and ambiguities were quite rare. The method has been found to be accurate, relatively simple to perform and fast. It is our method of choice for high resolution clinical HLA-A typing.

Alleles↗
PubMed2003

Study of MICA alleles in 201 African Americans by multiplexed single nucleotide extension (MSNE) typing.

We have developed a method for major histocompatibility complex class I chain-related gene A (MICA) genotyping using multiplexed single nucleotide extension (MSNE) and flow cytometric analysis of an array of fluorescent microspheres. This technique employs a polymerase chain reaction-derived target DNA containing all the polymorphic sites of MICA, synthetic complementary primers, biotinylated dideoxynucleotide triphosphate, fluorescent reporter molecules (streptavidin-phycoerythrin), and thermophilic DNA polymerase. Genomic DNA was amplified by MICA locus-specific primers and the MSNE reactions were carried out in the presence of 30 MSNE primers used to assay polymorphisms in exons 2, 3, and 4 of the MICA genes. Thirty-two previously typed cell lines were used as reference material. The MICA gene frequencies among 201 African-American unrelated donors were determined. Of 51 previously known alleles, 18 were observed in African-Americans, compared to 16 that were found in North American Caucasians and 9 in South American Indians, suggesting a more diversified allelic distribution in African-Americans. MICA*00201 and MICA*00801 were the two most frequent alleles in African-Americans. We observed a high degree of linkage disequilibrium between certain alleles of MICA and of human leukocyte antigen-B in the African-American population. The methodology described here offers a powerful new approach to DNA typing of the MICA alleles.

Black or African American↗
PubMed2003

Regulatory factors involved in cardiogenesis.

Determination of factors involved in cardiogenesis is fundamental to our understanding of heart growth and development. There are several families of transcription factors that play a role in cardiomyogenesis including the Nkx2, GATA, and MEF2 families. In this review, we describe factors implicated in development of cardiac tissues followed by a description of interactions among them.

Animals↗
PubMed2003

[Supplementing Qi and activating blood circulation in gene regulation of vascular smooth muscle cells].

According to the theory of traditional Chinese medicine, blood stasis is a main pathological mechanism in the development of vascular diseases. Supplementing Qi and activating blood circulation, as the therapeutic principle for the blood stasis, has been adapted. Studies demonstrated that the supplementing Qi and activating blood circulation recipe could regulate the expression of vasoactive peptides in vascular smooth muscle cells (VSMCs). The recipe inhibited the formation of neointima following arterial intimal lesions through down-regulating expression of proliferation-related genes and phenotypic modulation of VSMCs. The recipe also markedly inhibited the adhesion and migration of VSMCs and matrix remodelling by means of a mechanism that balances extracellular matrix turnover rate. The purpose of this review is to summarize the recent advances made in our understanding of new functions for the recipe in regulating VSMCs behaviours and their microenvironment relevant to vascular diseases and maintaining proper homeostasis.

Cell Division↗