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Biomedical subjects

Chun Zhang

Publications and source records attributed to Chun Zhang.

At least 73 records · Page 4Linked to original sources
PubMed2004

[Triploid crucain carp-allotetraploid hybrids (male) x goldfish( hermaphrodite)].

A new type of triploid crucian carp was generated by mating the males of the allotetraploid hybrids of red crucian carp (Carassius auratus red var.) (female) x common carp (Cyprinus carpio L.) (male), with the females the goldfish( Carassius auratus red var.) which was red in color and possessed the biforked tails. The biological characteristics of one-year old triploid crucian carp including the number and karotype of chromosome, gonadosomatic indices and gonadal structures, appearance and growth rate were investigated. The results indicated that the triploid crucian carp possessed 150 chromosomes with the karyotype: 33m + 51sm + 33st + 33t. In the breeding season, the gonadosomatic indices (GSI) of the ovaries and testes in the triplpoid crcuian carp were, respectively, lower than those in the diploid red crucian carp, and the tissue sections showed that both the ovaries and the testes in the triploid cruican carp were not able to produce the mature ova and sperm, respectively, indicating that they were sterile during one year. The triploid crucian carp was gray in color and had a single fork tail. They had other morphological traits intermediate to the paternal allotetraploid hybrids and the maternal goldfish, for example, one pair of very short and not readily visible barbells, the formula of lateral line scales: 31-6/7, 18 dorsal fin spines, and 0.5 in ratio of the width to the length of the body which was evidently higher than that (0.41) in another kind of triploid crucian carp called Xiangyun crucian carp, generated by crossing the males of the allotetraploid hybrids with the females of the Japanese crucain carp (Carassius auratus cuvieri T. et S.). Following 8-month culture, the triploid crucian carp averagely reached 350 gram in which the maximum individual weighed 550 gram. Among one- year old triploid crucian carp, the females grew faster than the males. Compared with Xiangyun crucian carp, the new type of triploid crucian carp not only presented some advantages the Xiangyun crucian carp had, for example, fast growth rate and potential sterility, but also got some new good performances like the high ratio of the width to the length of the body and the sweet flesh, suggesting they will be very potential in the commercial interest.

Animals↗
PubMed2004

[Studies on identification of Gryllotalpa by near-infrared diffuse reflectance spectrometry].

OBJECTIVE: To identify and analyse the different species, same species in different regions and confusion species. METHOD: Near-infrared diffuse reflectance spectrometry was used. RESULT: Clustering analysis showed that clustering relations were far among different Gryllotalpa species and close among the same species from different regions, and there were close relations among the same species from near regions and between Teleogryllus emmus and G. orientalis. CONCLUSION: Near-infrared diffuse reflectance spectrometry method can be used in classification and identification of Gryllotalpa.

Animals↗
PubMed2004

Protective effect of tetramethylpyrazine on learning and memory function in D-galactose-lesioned mice.

OBJECTIVE: To explore the protective effect of tetramethylpyrazine (TMP) on the learning and memory function in D-galactose (D-gal)-lesioned mice. METHODS: C57BL/6 mice were injected (s.c.) 2% D-gal for 40 days (100 mg x kg(-1) x d(-1)). Normal saline, TMP, and Huperzine A were respectively given by intragastric administration in different groups from the third week. Learning and memory ability was tested with Morris water maze for 5 days at the sixth week. After completion of behavioral test, the mice were sacrificed by decapitation. The brain was rapidly removed, and the cortex and hippocampus were separated. The superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in the cortex were determined. At the same time, the activity of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE), the binding sites (Bmax) and the affinity (KD) of M-cholinergic receptor in the cortex, and Bmax and KD of N-methyl-D-aspartate (NMDA) receptor in the hippocampus were determined. RESULTS: In this model group, (1) The deficit of learning and memory ability, (2) elevated MDA content and lowered SOD activity, (3) decreased AChE activity and M-cholinergic receptor binding sites in the cortex, and (4) lowered NMDA receptor binding sites were observed in the hippocampus, as compared with the normal control. TMP could markedly (1) attenuate cognitive dysfunction, (2) lower MDA content and elevate SOD activity, (3) increase the activity of ChAT and AChE, and M-cholinergic receptor binding sites in the cortex in the mice treated with D-gal. NMDA receptor binding sites were also increased in the hippocampus in the treated mice. CONCLUSION: TMP can significantly strengthen antioxidative function, improve central cholinergic system function, protect NMDA receptor activity, and thus enhance the learning and memory ability in D-gal-lesioned mice.

Alzheimer Disease↗
PubMed2004

[Study on Enrichment process of total flavones from Semen cuscutae with macroporous resin].

OBJECTIVE: To study the optimal conditions and parameters for the enrichment process of total flavones in Semen cuscutae with macroporous resin. METHODS: With the enrichment degree of total flavones in Semen cuscutae as an index, the optimal conditions of the enrichment process were investigated. RESULTS: The aqueous extract from Semen cuscutae was taken into the macroporous resin column, then the resin was washed by distilled water to get rid of impurity and 30% and 70% ethannol to elute total flavones. The above conditions were optimal. CONCLUSIONS: The process is feasible to enrich effective ingredient flavones from Semen cuscutae.

Adsorption↗
PubMed2003

Screening and characterization of human single-chain Fv antibody against beta-amyloid peptide 40.

Expression of single-chain variable fragment antibody on the surface of filamentous bacteriophage is widely used to make antibodies with pre-defined specificities. Using direct selection on solid phase-bound amyloid-beta 40 peptide, which is a main pathogenic feature of Alzheimer's disease, we obtained single-chain Fv antibody with specific binding activity. The binding epitope of the antibody is located between amino acids 1 and 16 of the peptide antigen. DNA sequencing showed that the gene coding for the single chain Fv antibody consists of 768 bp, and the complementarity-determining regions were deduced.

Amino Acid Sequence↗
PubMed2003

Effects of mycophenolate mofetil on renal interstitial fibrosis after Unilateral ureteral obstruction in rats.

To investigate the effects of mycophenolate mofetil (MMF) on the process of renal interstitial fibrosis, unilateral ureteral obstruction (UUO) model was established in rats. Twenty Sprague-Dawley rats underwent UUO and received vehicle (n = 10) or MMF (20 mg.kg-1.d-1, by daily gastric gavage, n = 10) during a period of 5 days following surgery, and the additional 10 rats were served as sham-operated group. The rats were killed 5 days after surgery. Immunohistochemistry was performed on renal tissue for proliferating cell nuclear antigen (PCNA), alpha-smooth muscle actin (alpha-SMA) and type I and III collagen (col I, col III). Histological studies were also done by MASSON staining. Five days after surgery, proliferating cells in tubules, interstitium as well as interstitial myofibroblast (MyoF) infiltration and interstitial col I, col III deposition were all significantly reduced by MMF treatment. MMF also alleviated the histological changes of UUO rats. These results suggested that the reduction of interstitial MyoF infiltration may be an important event by which MMF prevents renal injury caused by UUO and MMF could be used to limit the progression of renal fibrosis.

Animals↗
PubMed2003

The t(1;3) breakpoint-spanning genes LSAMP and NORE1 are involved in clear cell renal cell carcinomas.

By positional cloning, we identified two breakpoint-spanning genes in a familial clear cell renal cell carcinoma (CCRCC)-associated t(1;3)(q32.1;q13.3): LSAMP and NORE1 (RASSF1 homolog). Both genes are downregulated in 9 of 9 RCC cell lines. While the NORE1A promoter predominantly presents partial methylation in 6 of the cell lines and 17/53 (32%) primary tumors, the LSAMP promoter is completely methylated in 5 of 9 cell lines and in 14/53 (26%) sporadic and 4 familial CCRCCs. Expression of LSAMP and NORE1A proteins in CCRCC cell lines inhibited cell proliferation. These characteristics indicate that LSAMP and NORE1A may represent new candidate tumor suppressors for CCRCC.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Cloning and identification of a novel cDNA coding thioredoxin-related transmembrane protein 2.

Thioredoxin plays an important role in various cellular processes through redox regulation. Here we report the molecular cloning and characterization of one member of the thioredoxin superfamily, designated as TMX2. The TMX2 cDNA consists of 1644 nucleotides and contains an open reading frame encoding a protein of 372 amino acids with a predicted molecular mass of 42.5 kDa and an isoelectric point of 8.94. The TMX2 protein may possess an N-terminal signal peptide, a potential transmembrane domain, an Myb DNA-binding domain repeat signature, a thioredoxin consensus pattern, an endoplasmic reticulum (ER) membrane retention signal (KKXX-like motif), and a dileucine motif in the tail. Northern blot analysis shows it is widely expressed in human tissues.

Amino Acid Motifs↗
PubMed2003

Adeno-associated virus mediated LacZ gene transfect to cultured human iris pigment epithelium cells.

PURPOSE: To study the feasibility of adeno-associated virus mediated gene transfection to cultured human iris pigment epithelium (IPE) cells in vitro. METHODS: Recombinant replication deficient adeno-associated viruses (AAV) expressing LacZ gene were produced without helper virus. The LacZ gene was transduced into cultured human IPE cells. RESULTS: Cultured human IPE cells stained positively anticytokeratin, The titer of rAAV-LacZ was 2.1 x 10(8) virus particles/ml, 42% cultured human IPE cells expressed beta-galactosidase 7 days after transfection and 67% after 14 days. CONCLUSIONS: Recombined AAV produced without helper virus can transfer a foreign gene into human IPE cells with high efficiency in vitro.

Cells, Cultured↗
PubMed2003

[In vitro differentiation of embryonic stem cells mediated by the supernatant of retinal cells and retinoid acid].

PURPOSE: To analyse the differentiation features of embryonic stem cells which were induced by the supernatant of retinal cells and retinoid acid (RA). METHODS: Embryonic bodies (EB) were gained when embryonic stem cells (ESC) were propagated 1 generation after anabiosis. 3.5d EB without digestion were induced at four conditions sorted as condition A, B, C and D. A contains only retinoid acid (RA) in medium; B contains RA and the supernatant from retinal neurons and glia of mouse; C contains RA and the supernatant from retinal pigment epithelium of human; D contains RA and the supernatant of fetal retinal glia. The changes of embryonic stem cells were observed and the immune cytochemistry was adopted to detect the nestin, glial fibrillary acid protein (GFAP), cytokeratin, microtubule-associated protein 2 (MAP-2) and rhodopsin in induced cells. RESULTS: (1) The changes of differentiation features of EB: The characteristics for early stage were almost same at the four conditions. The cells with various shapes could be seen around EB. EB were dispersed 3 weeks later. Additionally, the cells which were no more abounded and not clear boundary appeared at condition A, the round cells with high transparency at condition B, EB and the cells around EB with apparent pigment at condition C, the large cells with simplex shape and glia-like appearance at condition D. (2) Immune cytochemistry showed that the most induced cells were MAP-2 (+) cells, no nestin (+) cells appeared at the four conditions. There were no GFAP, cytokeratin or rhodopsin positive cells in condition A; However, GFAP (+), cytokeratin (+) and rhodopsin(+) cells could be seen at condition B, cytokeratin positive cells at condition C, GFAP positive cells at condition D. CONCLUSION: RA can induce embryonic stem cells into neurons in second induction. Several kinds of the supernatant from retinal cells have an effect on induction of ESC. ESC can be differentiated into cells associated with the origin of the supernatant.

Animals↗
PubMed2003

[Study on the antisense inhibition effect of liposome-mediated radiolabled antisense oligonucleotides of c-myc mRNA].

OBJECTIVE: To ascertain whether liposome-mediated antisense oligonucleotides could inhibit the cancer cells from growing and the oncogene from expressing. METHODS: The antisense, sense and scrambled oligonucleotides for c-myc mRNA, each containing 15 bases, were synthesized elsewhere and were labeled with 99m-technetium (99mTc-DNA). Some of them were encapsulated with liposome. Then the 99mTc-DNA and the 99mTc-DNA entrapped with liposome were transfected into colon cancer cells, LS-174-T, with different radioactivity concentrations. At different time after transfection the uptake rate of cells was measured, and the reflow rate was detected at 18 h. Inhibition effect on cellular growth was tested by MTT colorimetric experiment and on the expression of c-myc by flow cytometry. RESULTS: The cellular uptake rate increased gradually after transfection within 5 hours, and that of liposome-mediated 99mTc-DNA was significantly higher than that of 99mTc-DNA. The reflow rate and fluorescence intensity of oncoprotein were 39.51 percent and 2.9860 +/- 0.3733 for antisense oligonucleotides, 44.12 percent and 4.2600 +/- 0.2218 for sense oligonucleotides, and 63.92 percent and 5.2620 +/- 0.8562 for mismatched oligonucleotides. The reflow rate and fluorescence intensity of liposome-entrapped 99mTc-labeled antisense oligonucleotide were significantly lower than those of sense and scrambled oligonucleotides. CONCLUSION: The liposome-mediated 99mTc-labeled antisense oligonucleotides could prohibit the cancer cells from growing and the oncogene from expressing.

Cell Division↗
PubMed2003

[The chromosome number and gonadal structure of F9-F11 allotetraploid crucian-carp].

In this paper, the chromosome number of F9-F11 hybridis of Red crucian (Carassius auratus) x common carp(Cryprinus carpio) was examined by means of kidney cell-PHA culture. The results showed that F9-F11 allotetraploids possessed 200 chromosomes, with the karyotype formula 44 m + 68 sm + 44 st + 44 t, which were the same as the data indicated in F3-F8 allotetraploids. Both female and male of F9-F11 allotetraploids had the normal ovaries and testes that were able to produce the normal dipoid ova and sperm. In nature conditions, without the injection of the extraneous hormone, the females and males of F9-F11 allotetraploids mated each other to produce new generation of tetraploids. With the stable genetic tetraploidy and the fertility in the nature environments, this allotetraploid population presented the key factors to form a new species with 200 chromosomes.

Animals↗
PubMed2003

[Effect of tetramethylpyrazine on learning, memory and cholinergic system in D-galactose-lesioned mice].

OBJECTIVE: To explore the effect of tetramethylpyrazine on learning, memory, and cholinergic system in D-galactose-lesioned mice. METHODS: C57BL/6J mice were given subcutaneous injection of 2% D-galactose for 40 days (100 mg.kg-1.d-1). Normal saline, tetramethylpyrazine (TMP) and Huperzine A (HupA) were given respectively by intragastric administration in different study groups from the third week on. Learning and memory ability were tested by Morris water maze for 5 days at the sixth week. Acetylcholinesterase (AchE) activity, the binding sites (Bmax) and the affinity (KD) of M-cholinergic receptor were determined. RESULTS: The learning and memory dysfunction, with lowered AchE activity and M-cholinergic receptor binding sites were found in the model group as compared with the normal control group. The tetramethylpyrazine, especially at the dose of 100 mg.kg-1.d-1, could markedly attenuate cognitive dysfunction, while elevate the lowered AchE activity (P < 0.05) and M-cholinergic receptor binding sites (P < 0.005) in the cerebral cortex of mice treated with D-galactose. CONCLUSIONS: The tetramethylpyrazine can significantly improve central cholinergic system function, and thus enhance the learning and memory ability in D-galactose-lesioned mice.

Acetylcholinesterase↗
PubMed2003

[Serum her-2/neu level and related factors in patients with breast cancer].

OBJECTIVE: To detect serum her-2/neu level in patients with breast cancer of different stages and its relationship with tissue her-2/neu overexpression as well as other factors. METHODS: A total of 120 women were alloted in this study, including 10 healthy volunteers, 31 breast benign disease patients, 53 primary breast cancer and 26 metastatic breast cancer patients. The level of serum her-2/neu was detected with enzyme-linked immunosorbent assay (ELISA). RESULTS: Elevated serum her-2/neu levels were observed in 0/10 healthy volunteers, 0/31 patients with benign tumor and 10/53 (18.9%) operable breast cancer patients. Serum concentration of soluble her-2/neu was correlated with tumor size (P < 0.05), but not with axillary lymph nodes nor estrogen receptor status. In patients with metastatic disease, soluble her-2/neu serum level was elevated in 61.5% (16/26) of patients, which was not correlated with the site of metastasis (P > 0.05). CONCLUSION: Serum her-2/neu level is correlated with tumor malignancy, stage and cancer load. It could be helpful in directing the treatment of recurrent or metastatic breast cancer.

Breast Neoplasms↗
PubMed2003

[Preparation of liposome-mediated 99m-technetium-labeled antisense oligonucleotides of c-myc mRNA].

To explore the preparation method of liposome-mediated 99m-technetium-labeled antisense oligonucleotides of c-myc mRNA and lay foundations for antisense imaging and treatment, antisense oligonucleotides (DNA) with 15 bases and di-functional chelate, hydrazino nicotinamide derivatives, were synthesized. After DNA combined with chelate, they were labeled with 99m-technetium to form compounds, 99mTc-chelate-DNA (99mTc-DNA), and were purified through Sep-Pak reverse column(C18, Waters) by using methanol and water as eluent. The leaching curve was made; the labeling efficiency was calculated. The products were then encapsulated with cation liposome to form liposome-mediated 99mTc-DNA. The radiochemical purity and stability of the liposome-mediated 99mTc-DNA were tested through strip chromatography. The labeling efficiency was 63.37% +/- 3.51% at the radioactive concentration of 1480 MBq, 62.52% +/- 3.69% at that of 740 MBq, 59.82% +/- 5.12% at that of 592 MBq. There were no significant differences between these labeling efficiencies. The radiochemical purity was 96.47% +/- 3.01%. The liposome-mediated radiolabeled antisense oligonucleotides were stable after incubation with water or serum. Therefore liposome-mediated radiolabeled antisense oligonucleotides could be obtained through hydrazino nicotinamide derivatives as di-functional chelate and liposome as vector.

DNA, Antisense↗
PubMed2002

Transcriptional activation of the human stress-inducible transcriptional repressor ATF3 gene promoter by p53.

Activating transcription factor 3 (ATF3) is an immediate early response gene that is induced in cells exposed to a variety of stress stimuli. In this report, upon exposure of cells to ultraviolet (UV) or proteasome inhibitor MG132, ATF3 protein was induced more efficiently in cells with intact p53 allele than in those with null mutant p53 allele. In Saos-2 cells harboring the temperature-sensitive mutant p53(Val-138), the expression of ATF3 gene was more significant at permissive temperature of 32.5 degrees C than at non-permissive 37.5 degrees C. Reporter assay of the human ATF3 gene promoter identified two p53-responsive elements at -379 to -370 and -351 to -342 from the transcriptional start site. These elements were capable of conferring p53 responsiveness to a heterologous promoter and specifically bound p53 protein in electrophoretic mobility shift assay. Furthermore, ATF3 gene promoter was more significantly activated by UV in cells with wild p53 allele. These results clearly show that the human ATF3 gene is one of the target genes directly activated by p53 and may suggest a functional link between stress-inducible transcriptional repressor ATF3 and p53.

Activating Transcription Factor 3↗
PubMed2002

Transcriptional repressor activating transcription factor 3 protects human umbilical vein endothelial cells from tumor necrosis factor-alpha-induced apoptosis through down-regulation of p53 transcription.

Activating transcription factor 3 (ATF3) is a transcriptional repressor that is rapidly induced in cells exposed to a wide range of stress stimuli. To clarify the role of ATF3 in determining cell fate, we overexpressed it in human umbilical vein endothelial cells (HUVECs) by adenovirus-mediated gene transfer. ATF3 protected these cells from tumor necrosis factor (TNF)-alpha-induced apoptosis, as measured by flow cytometric analysis, trypan blue exclusion assay, and cleavage of procaspase 3 and poly(ADP-ribose) polymerase. Northern blot and nuclear run on assay showed that the transcription of tumor suppressor gene p53 was down-regulated in the ATF3-overexpressing cells. In the transient expression assay, ATF3 suppressed the p53 gene promoter activity through its specific binding to an atypical AP-1 element, PF-1 site, in the p53 gene promoter. Furthermore, the cell-protecting effect of ATF3 was remarkably reduced in p53-deficient cells. These results demonstrate that overexpression of ATF3 suppresses TNF-alpha-induced cell death of HUVECs, at least in part, through down-regulating the transcription of p53 gene. ATF3 may function as a cell survival factor of endothelial cells during vascular inflammation and atherogenesis.

Activating Transcription Factor 3↗