Biomedical subjects

Yong Liu

Publications and source records attributed to Yong Liu.

229 records · Page 13Linked to original sources

PubMed2002

Changes of interleukin expression correlate with Helicobacter pylori infection and lymph node metastases in gastric carcinoma.

Helicobacter pylori (HP) infection induces expression of IL-8 and IL-10 in benign gastric epithelium. This study compared the expression of cytokines in CD4+ and CD8+ lymphocyte subsets of peripheral blood lymphocytes (PBL), benign mucosal lymphocytes (ML), and tumor infiltrative lymphocytes (TIL) as well as in the benign and malignant epithelial cells of the same patient, with respect to the presence of HP infection, lymph node metastases, and tumor histologic type. The mRNA of the cytokines was measured by a semiquantitative RT-PCR method. The levels were ranked and compared using the Wilcoxon sign-ranked test. Compared with CD8+ ML, the CD8+ TIL expresses higher levels of IL-6 and IL-8 but lower level of IL-4 in patients with lymph node metastases. In patients with HP infection, expression of IL-8 and IL-10 was higher in the gastric carcinoma cells than in the benign epithelial cells while expression of IL-6 and IL-8 were higher in CD8+ TIL than CD8+ ML. Overexpression of IL-8 in HP associated gastric carcinomas suggested that they might have arisen from HP-infected epithelial cells.

Adenocarcinoma↗

PubMed2002

[Study of rat osteoblasts transfected by transforming growth factor-beta 1 gene].

OBJECTIVE: To investigate the effect of transforming growth factor-beta 1 (TGF-beta 1) gene transfer on the biological characteristics of osteoblasts. METHODS: The expression of TGF-beta 1 in the transfected osteoblasts was detected by in situ hybridization and assay of TGF-beta 1 activity in the supernatant (mink lung epithelium cell growth-inhibition test). The effects of gene transfer and supernatant of the transfected osteoblasts on the proliferation and alkaline phosphatase(ALP) activity of osteoblasts were detected by 3H-TdR and MTT. RESULTS: The results of in situ hybridization analysis suggested that the osteoblasts transfected by TGF-beta 1 gene could express TGF-beta 1 obviously. The complex medium, which was the mixture of serum-free DMEM and the activated supernatant according to 1:1, 1:2, 1:4, could inhibit growth of Mv-1-Lu evidently and the ratios of inhibition were 16.3%, 22.7%, 28.2% respectively. TGF-beta 1 gene transfer had no effect on the biological characteristics of osteoblasts, but the activated supernatant of transfected osteoblasts stimulated proliferation and inhibited ALP activity of osteoblasts. CONCLUSION: TGF-beta 1 gene transfer promotes the expression of TGF-beta 1 and the biological characteristics of transfected osteoblasts are stable, which is helpful for gene therapy of bone defects in vivo.

Animals↗

PubMed2002

[Local cytokines profile in gastric cancer lesions].

OBJECTIVE: To study the characteristics of local cytokines profile in human gastric cancer lesions and offer guides for immunotherapy of gastric cancer. METHODS: The cytokines profile in isolated CD4+, CD8+ T subsets and epithelial cells from cancer tissue, contrasted with benign gastric mucosa of 15 gastric cancer patients were analyzed by a highly sensitive radioactivity labeled semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) technique. RESULTS: The predominance of increased Th2 and reduced Th1 immune response in both CD4+ and CD8+ T subsets from cancer tissue, compared with benign gastric mucosa, were observed. IL-6, IL-8 and TNF-alpha in CD8+ T cells from cancer tissue showed statistical higher levels than those from benign gastric mucosa (P = 0.029, P = 0.022, P = 0.002), so did IL-10, TGF-beta, TNF-alpha in T cells and epithelial cells. CONCLUSION: A shift of Th1/Th2 cytokines to Th2 is found in T cells from local tumor lesion of gastric cancer, which suggests an immune suppressive status in local tumor lesion. The obvious change of cytokine profile in CD8+ T cell suggests they play a main role in immune suppression. To study the cytokine expression of different cell subsets, we are able to offer guides for immunotherapy for patients with gastric cancer.

Adult↗

PubMed2002

[Stimulation effect of anthracene on marine microalgae growth].

Two species of marine microalgae, Isochrysis galbana 8701 and Skeletonema costatum, were exposed to low concentration of anthracene, and their cell density, contents of chlorophyll a, carotinoid and protein, and superoxide dismutase (SOD) activity were examined. It was showed that low concentration of anthracene (1.5-6.0 micrograms.L) could obviously stimulate the growth of these microalgae, and their protein, chlorophyll a, and carotinoid contents increased with increasing cell density. SOD of treated groups remained high activity, compared with the controlled group during the whole experiment.

Anthracenes↗

PubMed2002

Expanded T cell clones and cytokines expression in human gastric carcinomas of different histological types.

OBJECTIVE: To study the characteristics of host immune response against human gastric carcinoma of different histological types. METHODS: The expression of 24 families of T cell receptor beta chain variable region (TCRVbeta) and cytokine profiles in isolated CD4(+) and CD8(+) subsets, as well as the cytokine profiles in purified epithelial cells from the tumor tissue and the residual benign tissue of patients with gastric carcinoma, was detected by a highly sensitive radioactivity labeled semi-quantitative RT-PCR technique. RESULTS: The number of expanded T cell clones in CD8(+) subset from tumor tissue of the intestinal-type carcinoma was larger than that of diffuse-type (P = 0.046). The mRNA levels of IL-6, IL-8 in CD8(+) T subset, as well as the level of TNF-alpha in CD4(+) T subset from the tumor tissue of the diffuse type (0.61 +/- 0.29, 0.56 +/- 0.22, 0.09 +/- 0.03) were significantly higher than that from the residual benign tissue (0.14 +/- 0.05, 0.27 +/- 0.09, 0.04 +/- 0.02; P = 0.028, P = 0.043, P = 0.046). However, the mRNA level of IL-8 in CD8(+) subset and epithelial tumor cells of the intestinal-type (0.57 +/- 0.25, 0.27 +/- 0.07) was significantly higher than that from the residual benign tissue (0.21 +/- 0.07, 0.14 +/- 0.06; P = 0.028, P = 0.028). CONCLUSIONS: The characteristics of host immune response against tumor are different between intestinal-type and diffuse-type gastric carcinoma. Both fewer expanded T cell clones and more suppressive cytokines suggest a more suppressive immune status in the local tumor lesion of diffuse-type than in the intestinal-type of the gastric carcinoma.

Adult↗

PubMed2002

Defective 3A trophoblast-endometrial cell adhesion and altered 3A growth and survival by human papillomavirus type 16 oncogenes.

Human papillomaviruses (HPVs) are found in trophoblasts of spontaneous abortions and replicate in these cells in culture. We used recombinant adeno-associated viruses (rAAV) to introduce the HPV-16 E6 and E7 oncogenes into 3A trophoblasts. AAV/E7/Neo-infected 3A trophoblasts died rapidly, but AAV/E6/Neo- and AAV/E6-E7/Neo-infected cells grew more rapidly than AAV/Neo-infected 3A cells and parental 3A. After G418 selection, the resulting E6-E7/3A and E6/3A cell lines were found to be highly defective for binding RL95 and HEC endometrial cells compared to Neo/3A and parental 3A. Serum requirements and soft agar colony formation analysis showed that E6-E7/3A had the most malignant phenotype, followed by E6/3A, with parental 3A cells having the lowest. E6/3A and E6-E7/3A were also immortal. Thus, HPV-16 oncogene expression may lead to outright trophoblast death, defective endometrial cell recognition, or a malignant phenotype. Any of these changes might lead to disruption/dysfunction of the trophoblast layer/gestational loss.

Apoptosis↗

PubMed2002

[Genetic diversity analysis of mitochondrial D-loop region of Chinese sucker (Myxocyprinus asiaticus)].

Chinese sucker, Myxocyprinus asiaticus, is an endemic species of China and also the only representatives of family Catostomidae in Asia. The fish was naturally distributed in Yangtze River and Mingjiang River and now few could be captured because of pollution and overexploitation. The fish has been listed in the second class of preserved animal in China. Studying and assessing its population structure is an imperative and fundamental work for making effective protection strategies. We amplified and sequenced the D-loop region of mtDNA of 8 samples. The size of the D-loop region is about 958 bp. A total of 32 variation loci were detected and the mutation rate was 0.033. All the mutation came from nucleotide substitution except one nucleotide deletion. Most of the nucleotide variations were found between the 55-365 bp region. The individual mutation rate varied from 0-1.36%, which exhibited nucleotide polymorphism to some extent among 8 samples. Compared with RAPD and other PCR-based methods, the directily sequencing of mtDNA D-loop region revealed much more genetic diversity. Meanwhile, the D-loop region of Moxostoma robustum derived from GenBank was aligned with that of Chinese sucker through CLUSTAL software. By comparison, we found that the mutation rate (0.033) of D-loop of Chinese sucker is higher than that of Moxostoma robustum (0.016).

Animals↗

PubMed2002

[Comparative study of transurethral electrovaporization of prostate versus transurethral resection of prostate on benign prostatic hyperplasia].

OBJECTIVES: To compare the efficacy of transurethral electrovaporization of prostate (TUVP) with transurethral resection of prostate (TURP). METHODS: 206 patients with symptomatic benign prostatic hyperplasia (BPH) whose prostatic sizes were all less than 60 grams were randomly divided into two groups. 97 cases were treated by TUVP while the other 109 cases were treated by TURP. The patients who underwent either TUVP or TURP were followed up for 12-34 months with an average of 20 months postoperatively. RESULTS: Both groups showed the significant decline in the mean IPSS (international prostatic symptom score) (P < 0.01), the mean PVR (Postovoiding Residual Volume) (P < 0.01), while increase in mean Qmax (Peak uroflow rate) (P < 0.01) in 12 months, 24 months after the operation. There were significant differences in the mean duration of operation or catheterization postoperatively (P < 0.05). The main complications of post-operation in the two groups were stress incontinence, TUR syndrome, urethral stricture, secondary bleeding. CONCLUSIONS: Both TUVP and TURP are effective treatment for the patient with BPH whose prostatic size is less than 60 grams. TUVP spends shorter time of the operation and postoperative catheterization than that of TURP.

Aged↗

PubMed2002

[Purification and identification of recombinant nuclear protein of Hantaan virus].

OBJECTIVE: To purify recombinant nuclear protein of Hantaan virus. METHODS: The recombinant plasmid was transformed into E.coli and induced by IPTG. The expressed protein is a fusion protein with GST and existed in inclusion bodies. The inclusion bodies were processed through denaturation and renaturation and were purified with Glutathione Sepharose 4B affinity chromatography column. Then the purified fusion protein and nuclear protein were examined by sandwich ELISA and Western blot. RESULTS: The expressed fusion protein was separated from the mixture proteins by the first affinity chromatography. GST was cut from the purified fusion protein with thrombin. The nuclear protein was separated from GST by the second affinity chromatography. The crossed peak represents nuclear protein and the elute peak represents GST. The purified fusion protein and nuclear protein were single band by SDS-PAGE. Both of them had available antigen activity. CONCLUSIONS: Purification of nuclear protein of Hantaan virus with Glutathione Sepharose 4B affinity chromatography is an effective method.

Blotting, Western↗

PubMed2002

Expression of rhBMP-7 gene in transduced bone marrow derived stromal cells.

OBJECTIVE: To explore the possibility of expression of exogenous gene in transduced bone marrow derived stromal cells (BMSCs). METHODS: The marker gene, pbLacZ, was transferred into cultured BMSCs and the expression of transduced gene by X-gal staining was examined. Then plasmid pcDNA3-rhBMP7 was delivered to cultured BMSCs. Through immunohistochemical staining and RT-PCR assay, the expression of rhBMP7 gene was detected. RESULTS: The exogenous gene could be expressed efficiently in transduced BMSCs. CONCLUSION: The present study provided a theoretical basis to gene therapy on the problems of bone and cartilage tissue.

Animals↗

PubMed2002

[Studies on chemical constituents of Salvia roborowskii Maxim].

OBJECTIVE: To study the chemical constituents from Salvia roborowskii Maxim. METHODS: Chromatography and spectroscopic analysis were employed to isolate and elucidate the chemical constituents in the plant. RESULTS: Six compounds were isolated and elucidated as lupeol (I), 11 beta-hydroxy-lupeol(II),3 beta-acetyl-11 beta-hydroxy-lupeol(III), ursolic acid (IV), beta-sitosterol(V), daucosterol (VI). CONCLUSION: I approximately VI were isolated from this plant for the first time.

Chromatography, Thin Layer↗

PubMed2001

Strain-based genetic differences regulate the efficiency of systemic gene delivery as well as expression.

We have characterized the impact of strain-based genetic differences on the efficiency of the intravenous cationic liposome-DNA complex (CLDC)-based gene transfer and expression in mice. We also investigated what steps in the gene delivery and expression pathway appeared responsible for these strain-related differences and whether such differences could be compensated for either by agents that alter host pathways important in CLDC-mediated gene transfer and expression, or by changes in CLDC formulation. We found that different mouse strains can exhibit different expression levels and/or differences in the amount of plasmid DNA delivered to the organs where the DNA is expressed. Furthermore, drug pretreatment or reformulation of the CLDC could improve DNA delivery and/or gene expression in a strain-specific fashion. We conclude that genetic factors critically modify both the tissue deposition and the expression of genetic materials delivered by CLDC. Because manipulation of either the host or the CLDC could at least partially compensate for these strain-related differences, such strategies may be required to effectively use non-viral gene transfer approaches in genetically diverse populations.

Animals↗

PubMedDate not supplied

Generation of recombinant skin in vitro by adeno-associated virus type 2 vector transduction.

It has long been recognized that skin may be a particularly good target for pharmacologic gene therapy and as a platform for the secretion of systemically distributed molecules. Adeno-associated virus type 2 (AAV) is a useful vector for skin gene therapy because skin is the natural host tissue for AAV, in which it functions as an autonomous parvovirus. We demonstrate here that recombinant (r) AAV vectors carrying the granulocyte-macrophage colony-stimulating factor (GM-CSF), human papillomavirus E6, or green fluorescent protein (GFP) transgene could transduce primary human keratinocytes in ex vivo culture. We further demonstrate that these transduced cells could be used to form a transgene-positive recombinant skin (r-skin), using the organotypic epithelial raft culture system. Transduction of keratinocytes was demonstrated by reverse transcriptase-polymerase chain reaction (RT-PCR) for RNA expression, enzyme-linked immunosorbent assay (ELISA) for product secretion, intracellular staining for protein expression, vector-chromosomal junction PCR and Southern blot analysis of proviral sequences, in situ immunohistochemistry analysis of protein expression, and ultraviolet light fluorescence for GFP expression. AAV/GM-CSF/Neo-infected keratinocyte/raft skins secreted GM-CSF at levels as high as 25 ng/cm(2) of skin and maintained expression to 60 days postinfection. These data support the utility and efficiency of AAV-based gene delivery to produce genetically altered keratinocytes and r-skin.

Cell Culture Techniques↗