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Biomedical subjects

Ying Liu

Publications and source records attributed to Ying Liu.

At least 307 records · Page 17Linked to original sources
PubMed2004

Inhibition of hemangiogenesis and lymphangiogenesis after normal-risk corneal transplantation by neutralizing VEGF promotes graft survival.

PURPOSE: To evaluate the occurrence and time course of hem- and lymphangiogenesis after normal-risk corneal transplantation in the mouse model and to test whether pharmacologic strategies inhibiting both processes improve long-term graft survival. METHODS: Normal-risk allogeneic (C57BL/6 to BALB/c) and syngeneic (BALB/c to BALB/c) corneal transplantations were performed and occurrence and time course of hem- and lymphangiogenesis after keratoplasty was observed, by using double immunofluorescence of corneal flatmounts (with CD31 as a panendothelial and LYVE-1 as a lymphatic vascular endothelium-specific marker). A molecular trap designed to eliminate VEGF-A (VEGF Trap(R1R2); 12.5 mg/kg) was tested for its ability to inhibit both processes after keratoplasty and to promote long-term graft survival (intraperitoneal injections on the day of surgery and 3, 7, and 14 days later). RESULTS: No blood or lymph vessels were detectable immediately after normal-risk transplantation in either donor or host cornea, but hem- and lymphangiogenesis were clearly visible at day 3 after transplantation. Both vessel types reached donor tissue at 1 week after allografting and similarly after syngeneic grafting. Early postoperative trapping of VEGF-A significantly reduced both hem- and lymphangiogenesis and significantly improved long-term graft survival (78% vs. 40%; P < 0.05). CONCLUSIONS: There is concurrent, VEGF-A-dependent hem- and lymphangiogenesis after normal-risk keratoplasty within the preoperatively avascular recipient bed. Inhibition of hem- and lymphangiogenesis (afferent and efferent arm of an immune response) after normal-risk corneal transplantation improves long-term graft survival, establishing early postoperative hem- and lymphangiogenesis as novel risk factors for graft rejection even in low-risk eyes.

Animals↗
PubMed2004

Lysine-fortified wheat flour improves the nutritional and immunological status of wheat-eating families in northern China.

The purpose of this study was to determine the impact of the fortification of wheat flour with lysine on selected health indicators among farm families obtaining 58% to 67% of their dietary protein from wheat. A man, a woman, and a child aged 5 to 12 years were studied from each of 88 families in a village near Huixian City, Henan Province, China. Half of the families received wheat flour fortified with 3 g of lysine per kilogram for three months, and the other half received wheat flour without fortification. The results showed a significantly greater gain in the height and weight of children receiving lysine-fortified wheat flour. Hemoglobin values were not affected. The mean prealbumin values of adult men and women were higher in those receiving lysine. The numbers of CD3 T cells increased significantly in women and children, as did the complement fraction C3 and IgG in men, IgA in women, and IgG, IgA, IgM, and C3 in children. These results indicate that lysine fortification of wheat flour can significantly improve some indicators of the nutritional status and immune function of family members consuming a wheat-based diet.

Adult↗
PubMed2004

Distinct activities of Msx1 and Msx3 in dorsal neural tube development.

Patterning of the dorsal neural tube involves Bmp signaling, which results in activation of multiple pathways leading to the formation of neural crest, roof plate and dorsal interneuron cell types. We show that constitutive activation of Bmp signaling at early stages (HH10-12) of chick neural tube development induces roof-plate cell fate, accompanied by an increase of programmed cell death and a repression of neuronal differentiation. These activities are mimicked by the overexpression of the homeodomain transcription factor Msx1, a factor known to be induced by Bmp signaling. By contrast, the closely related factor, Msx3, does not have these activities. At later stages of neural tube development (HH14-16), dorsal progenitor cells lose their competence to generate roof-plate cells in response to Bmp signaling and instead generate dorsal interneurons. This aspect of Bmp signaling is phenocopied by the overexpression of Msx3 but not Msx1. Taken together, these results suggest that these two different Msx family members can mediate distinct aspects of Bmp signaling during neural tube development.

Animals↗
PubMed2004

Production of transgenic blastocyst by nuclear transfer from different types of somatic cells in cattle.

The present study examined the effects of genetic manipulation to the donor cell and different types of transgenic donor cells on developmental potential of bovine nuclear transfer (NT) embryos. Four types of bovine somatic cells, including granulosa cells, fetal fibroblasts, fetal oviduct epithelial cells and fetal ovary epithelial cells, were transfected with a plasmid (pCE-EGFP-Ires-Neo-dNdB) containing the enhanced green fluorescent protein (EGFP) and neomycin-resistant (Neor) genes by electroporation. After 14 days selection with 800 microg/mL G418, transgenic cell lines from each type of somatic cells were obtained. Nontransgenic granulosa cells and all 4 types of transgenic somatic cells were used as nuclear donor to produce transgenic embryos by NT. There was no significant difference in development rates to the blastocyst stage for NT embryos from transgenic and nontransgenic granulosa cells (44.6% and 42.8%, respectively), and transfer of NT embryos derived from transgenic and nontransgenic granulosa cells to recipients resulted in similar pregnancy rates on day 90 (19% and 25%, respectively). The development rates to the blastocyst stage of NT embryos were significantly different among different types of transgenic donor cells (P<0.05). Blastocyst rates from fetal oviduct epithelial cell and granulosa cell (49.1% and 44.6%, respectively) were higher than those from fetal fibroblast (32.7%) and fetal ovary epithelial cell (22.5%). These results suggest that (i) genetic manipulation to donor cells has no negative effect on in vitro and early in vivo developmental competence of bovine NT embryos and (ii) granulosa and fetal oviduct epithelial cells can be used to produce transgenic bovine NT embryos more efficiently. In addition, GFP can be used to select transgenic NT embryos as a non-invasive selective marker.

Animals↗
PubMed2004

Generation of cloned calves from different types of somatic cells.

Six types of bovine somatic cell lines, including a granulosa cell line of Chinese red-breed yellow cattle (YGR), a granulosa cell line of Holstein cow (HGR), two skin fibroblast cell lines of two adult Holstein cows respectively (AFB1 and AFB2), a skin fibroblast cell line (FFB) and an oviduct epithelial cell line (FOV) of a Holstein fetus, were established. Somatic cell nuclear transfer (SCNT) was carried out using these cells as nuclei donor, and a total of 12 healthy calves were cloned. The effects of different types of donor cells on developmental potential of bovine SCNT embryos were investigated. (i) There was no significant difference in development rates to the blastocyst stage for SCNT embryos from YGR and HGR (33.2% and 35.1%, respectively). Pregnancy rates of them were 33.3% and 30.2%, respectively; and birth rates were 16.7% and 11.6%, respectively. (ii) Development rates to the blastocyst stage for SCNT embryos from different individuals (AFB1 and AFB2) differed significantly (27.9% and 39.4%, respectively, P < 0.05). Pregnancy rates of them were 36.2% and 36.4%, respectively; and birth rates were 14.9 % and 27.3%, respectively. (iii) There was significant difference in development rates to the blastocyst stage for SCNT embryos from FFB and FOV of the same fetus (37.9% and 41.5%, respectively, P < 0.05). Pregnancy rates of them were 45.7% and 24.1%, respectively; and birth rates were 22.9% and 10.3%, respectively. Finally, developmental potential of bovine SCNT embryos from all four types of somatic cells from Holstein cows (HGR, AFB, FFB and FOV) were compared. For in vitro development stage, development rates to the blastocyst stage for SCNT embryos from HGR, AFB, FFB and FOV were 35.1%A, 29.4%B, 37.9%A and 41.5%c, respectively (pABC < 0.05); for in vivo development stage, pregnancy rates of them were 30.2%, 36.2%, 45.7% and 24.1%, respectively; and birth rates of them were 11.6%, 17.2%, 22.9% and 10.3% respectively.

Animals↗
PubMed2004

Role of prehypertension in the development of coronary atherosclerosis in Japan.

BACKGROUND: Hypertension is an important risk factor of coronary heart disease. A new guidelines for hypertension prevention and management in The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure in the United States recommended lifestyle modification or medical treatment for subjects with prehypertension. However, whether prehypertension increases the risk of coronary atherosclerosis in the Japanese population is still unknown. METHODS: A cross-sectional study in a clinical setting was conducted. The subjects were 705 patients (417 males and 288 females) aged 30 years and older who underwent a first-time coronary angiography for suspected or known coronary heart disease at 5 major cardiology departments in the Fukuoka metropolitan area between September 1996 and August 1997. RESULTS: Compared to subjects with normal blood pressure, those with prehypertension had an increased risk of coronary atherosclerosis even after adjusting for other factors. CONCLUSION: Prehypertension may be an important clinical entity which requires treatment in the Japanese population.

Adult↗
PubMed2004

[Characteristics of immunoglobulin heavy chain variable region genes in childhood B-cell acute lymphoblastic leukemia].

OBJECTIVE: To investigate the origin of childhood B-cell acute lymphoblastic leukemia (B-ALL) and its epitopes recognized by cytotoxic T lymphocytes (CTL) in immunoglobulin heavy chain variable region (IgHV). METHODS: Seven IgHV gene families were respectively amplified by PCR and directly sequenced in 108 childhood ALL. The amino acid sequences were deducted from sequenced nucleotides. Bioinformatics was applied to analyses of recombination patterns, somatic mutations and germline gene segments usage, and to prediction of epitopes recognized by CTL. RESULTS: IgHV gene rearrangements were identified in 66% of the cases, including 37 (52.1%) monoallelic rearrangements, 26 (36.6%) biallelic rearrangements and 8 (11.3%) oligoclonal rearrangements. Among the obtained 40 B-ALL IgHV gene sequences, 8 (20.0%) were in frame rearrangements without stop codons. V(H3) (11/40), V(H4) (11/40) and V(H1) (8/40) amounted to 75% rearranged V(H) families. V(H)(4-59) and V(H)(4-34) were the most frequently rearranged V(H)(4) family gene segments. Usage of D2 and D3 families was most prominent (35.9% and 28.2%, respectively). Increased frequency of D7-27 (15.4%) was found as compared to that of normal peripheral B lymphocytes (P = 0.02). J(H)(6) was found in 47.5% rearrangements followed by J(H)(4) (27.5%). 8/40 (20.0%) DJ(H) junctions lacked N nucleotides, which was higher than that reported for normal peripheral B lymphocytes (P = 0.02). 17.5% B-ALL IgHV contained scattered replacement mutations with replacement (R) to silent (S) substitution ratio (R/S ratio) <or= 1 in complementarity determining region (CDR). Above 80% potential HLA class I molecule-binding peptides were derived from framework regions of immunoglobulin heavy chains in 26 B-ALL cases and 1 - 2 peptides of the same IgHV family were shared by B-ALL. CONCLUSION: B-ALL originated from progenitor or precursor B lymphocytes. B-ALL IgHV genes are of germline characteristics. Potential T cell epitopes were derived from framework regions 1 and 3 of immunoglobulin heavy chain in B-ALL.

Adolescent↗
PubMed2004

[Clinical and experimental study of cardiac effects of conventional dosage arsenic trioxide in APL patients].

OBJECTIVE: To investigate cardiac effects of arsenic trioxide (As(2)O(3)) at conventional dosage in acute promyelocytic leukemia (APL) patients. METHODS: The basical heart rate, electrocardiograph, plasma As(2)O(3) concentration of APL patients were dynamically monitored. The action potential duration and current of I(Ca-L) in guinea pig cardiac ventricular myocytes were assayed by patch clamp technique, and the elevated cytosolic [Ca(2+)]i of guinea pig ventricular myocytes induced by As(2)O(3) by laser confocal microscopy. RESULTS: Approximately 52.5% - 35% of 40 APL patients manifested poor cardiac effects of different degree when As(2)O(3) intravenous infused at conventional doses in the initial 1 or 2 weeks with fast heart rate or prolonged QT interval. As(2)O(3) at concentration of 1, 2, 5 micro mol/L prolonged action potential duration from (563.0 +/- 55.8) ms to (737.7 +/- 131.7), (842.4 +/- 115.6) and (1103.2 +/- 96.3) ms respectively (P < 0.05, P < 0.01, P < 0.01), and increased I(Ca-L) of guinea pig cardiac ventricular myocytes as well as the respectively cytosolic [Ca(2+)]i. Calcium channel blocking agent can cut-out the effect. CONCLUSION: As(2)O(3) intravenous infusion at conventional doses can cause tachycardia and prolong QT interval. The probable mechanism might be that As(2)O(3) affects the ion channels and cytosolic calcium.

Adult↗
PubMed2004

[Human oral carcinoma-associated fibroblasts: its cultivation, purification and identification].

OBJECTIVE: To separate, cultivate, purify and identify oral carcinoma-associated fibroblasts (CAFs) preliminarily. METHODS: The primary oral CAFs and normal fibrolasts (NFs) of oral mucosa were obtained by tissue culture. Then cells were dissociated by 0.25% trypsin and purified by curettage method and trypsinization. Morphological characteristics were observed under light microscope and electron microscope. The certain proteins were examined by immunohistochemistry (SP method). RESULTS: The third passage purified oral CAFs were maintained. The characteristics of shape and growth of the oral CAFs changed significantly comparing to the NFs. Myofilament and electron dense patch were showed in the oral CAFs by electron microscope. The oral CAFs showed negative staining for cytokeratin, and positive staining for vimentin, alpha-smooth muscle actin and matrix metalloproteinases-2. CONCLUSIONS: There are obvious differences of the morphological characteristics and expression of certain proteins between the CAFs and NFs. The microecology of the oral tumor-host interface might be one of the most important factors affecting the CAFs.

Cell Culture Techniques↗
PubMed2004

[Effects of emodin on the intracellular calcium concentration ([Ca2+]i) and L-type calcium current of the single ventricular mytocytes from guinea pig].

AIM: To study the effects of emodin on intracellular calcium concentration ([Ca2+]i) and L-type calcium current of the single ventricular myocytes from guinea pig. METHODS: Enzymatic dissociation was used to isolate single ventricular myocytes from adult guinea pig. They were loaded with Ca2(+)-sensitive fluorecent indicator Fluo-3/AM. [Ca2+]i represented by fluorescent intensity (FI) was measured by laser scanning confocal microscope. Whole cell patch clamp technique was used to record ICa-L. RESULTS: At resting status, [Ca2+]i was not affected by emodin (1-100 mumol.L-1). Emodin at the concentration of 1 mumol.L-1 was shown to increase the [Ca2+]i induced by 60 mmol.L-1 KCl. The peak value of fluorescent intensity was increased from 1,877 +/- 551 to 2,905 +/- 739 (n = 8, P < 0.05). Emodin at the concentration of 10 mumol.L-1 had no effect on the increase of [Ca2+]i induced by 60 mmol.L-1 KCl. However, the increase of [Ca2+]i induced by KCl was reduced to 1,214 +/- 335 (n = 8, P < 0.05) by 100 mumol.L-1 emodin. The density of ICa-L was increased from (-6.2 +/- 1.3) pA/pF to (-8.3 +/- 0.3) pA/pF (n = 6, P < 0.05) by 1 mumol.L-1 emodin at the test pulse of 0 mV. The current was not altered by 10 mumol.L-1 emodin. But it was inhibited from (-6.6 +/- 1.0) pA/pF to (-3.80 +/- 0.16) pA/pF (n = 6, P < 0.05) by 100 mumol.L-1 emodin at the test pulse of +10 mV. CONCLUSION: Emodin has two-way regulation on [Ca2+]i and ICa-L of cardiomyocytes in guinea pig.

Animals↗
PubMed2004

[Tumor antigen-specific cytotoxic T lymphocytes and cancer immunotherapy - review].

Tumor antigen-specific cytotoxic T lymphocytes are important anti-cancer cells. The focuses of this review are to introduce the molecular basis of antigen presentation and CTL recognition, to summarize the identification of tumor associated antigens and their T cell epitopes, to highlight the current insights into the immunogenicity of TAA peptides and the principles of peptide-based vaccines against cancer, and to comment on future prospects for CTL therapy.

Animals↗
PubMed2004

[The effect of postoperative chemotherapy after esophagectomy on the survival rate to patients with original squamous cell carcinoma of esophagus].

OBJECTIVE: To study the prognostic factors affecting the survival rate after extended radical esophagectomy with three-field lymph node dissection for squamous cell carcinoma and the effect of postoperative chemotherapy. METHODS: Out of 126 patients with original squamous cell carcinoma of esophagus who accepted extended radical esophagectomy with three-field lymph node dissection from 1987 - 1992 in a hospital, 97 of them were included in this study. Data on the clinical/pathological characters and post surgery survival records of the subjects' were collected. Survival analysis methods included Kaplan-Meier, Log-rank test and Cox multivariable model and the effects of postoperative chemotherapy were analyzed for patients in early and late stages. RESULTS: There was no significant difference in clinical and pathological character between those patients only undergone surgery and patients accepting postoperative chemotherapy. The size of tumor, grade of differentiation of the tumor cells, infiltration deepness, with or without lymph node metastasis, expression of nm23 and EGFR and treatment after surgery etc. were correlated with the survival rate. For patients in early tumor stage, postoperative chemotherapy with cisplatin and 5-FU after surgery seemed to be a risk factor. For patients in late stage, postoperative chemotherapy with cisplatin and 5-FU after surgery did not seem to improve survival rate. CONCLUSION: It is imperative to study on the effect of adjuvant postoperative chemotherapy to patients, especially those at early stage with squamous cell carcinoma of esophagus. Doctors must be scrupulous when making decisions.

Adult↗
PubMed2004

[Construction of replication-deficient recombinant adenovirus expressing gag-polDelta and gp140TM genes of human immunodeficiency virus in mice].

BACKGROUND: Construction of replication-deficient recombinant adenovirus expressing gag-pol and env genes of human immunodeficiency virus (HIV) in mice. METHODS: gag-polDelta and gp140TM genes were cloned into shuttle vector pAdTrack-CMV respectively, and then the plasmids containing gag-polDelta or gp140TM gene were cotransformed with the backbone of adenovirus into E.coli BJ5183. Transfections of the recombinants were performed to obtain recombinant adenoviruses. Its immunogenicity was evaluated by testing antibody levels of mice primed with DNA vaccines and boosted with recombinant adenoviruses. RESULTS: The replication-deficient recombinant adenovirus could express Gp140TM, Gag P55 and P24 proteins correctly. The mice primed with DNA vaccines and boosted with recombinant adenoviruses elicited high titer of HIV-1-specific antibody compared with that inoculated with DNA vaccines only. CONCLUSION: Replication-deficient recombinant adenovirus expressing gag-polDelta and gp140TM can elicit high titer HIV-1-specific antibodies.

AIDS Vaccines↗
PubMed2004

[The construction of attenuated Tiantan recombinant vaccinia virus vector with IFN-gamma receptor gene deletion].

OBJECTIVE: B8R gene encodes a secreted protein with homology to IFN-gamma receptor, which neutralizes the antiviral and immunological regulation activities of IFN-gamma. To improve the safety of vaccinia virus vector, an attenuated recombinant vaccinia virus with the B8R gene deletion from Tiantan vaccine strain (VTT) was constructed. METHODS: The transfer vectors were generated by joining B8R left flank, B8R right flank, vv promoter, LacZ, multicloning site and pBRSK fragments. The recombinant viruses VTTdeltaB8RLacZ (VTT with B8R deletion and LacZ insertion) were constructed by homologous recombination. RESULTS: The B8R deletion mutants were confirmed by dot blot with B8R gene probe and PCR amplification. The replication ability of VTTdeltaB8RLacZ strain in vitro was similar to that of the VTT. The skin lesions formed by VTTdeltaB8RLacZ (10(6) pfu) were significantly smaller and healed faster than those formed by VTT when injected intradermally to the rabbits,and no visible ulceration occurred. Meanwhile LacZ in VTKgpedeltaB8RLacZ was expressed stably. CONCLUSIONS: The attenuated vector with B8R gene deletion improves the safety of recombinant vaccinia virus vaccine B8R locus may be used as a new site for insertion of foreign genes in vaccinia virus vector.

Animals↗
PubMed2004

Text mining functional keywords associated with genes.

Modern experimental techniques provide the ability to gather vast amounts of biological data in a single experiment (e.g. DNA microarray experiment), making it extremely difficult for the researcher to interpret the data and form conclusions about the functions of the genes. Current approaches provide useful information that organizes or relates genes, but a major shortcoming is they either do not address specific functions of the genes or are constrained by functions predefined in other databases, which can be biased, incomplete, or out-of-date. We extended Andrade and Valencia's method [1] to statistically mine functional keywords associated with genes from MEDLINE abstracts. The MEDLINE abstracts are analyzed statistically to score and rank keywords for each gene using a background set of words for baseline frequencies. We generally got very good functional keyword information about the genes we tested, which was confirmed by searching for the individual keywords in context. The keywords extracted by our algorithm reveal a wealth of potential functional concepts, which were not represented in existing public databases. We feel that this approach is general enough to apply to medical and biological literature to find other relationships: drugs vs. genes, risk-factors vs. genes, etc.

Algorithms↗
PubMed2004

Polymorphisms of renin-angiotensin system in essential hypertension in Chinese Tibetans.

OBJECTIVE: To evaluate the potential implications of the genetic variability of angiotensin converting enzyme, angiotensinogen and angiotensin II type 1 receptor gene for essential hypertension in Tibetan. METHODS: A case-control study was conducted in 173 hypertensive individuals and 193 individuals with normal blood pressure. Multiple logistic regression analyses were used to estimate the risks of developing hypertension for different genotypes, and haplotype analyses of the angiotensinogen gene were used to determine the association between two-locus angiotensinogen gene polymorphisms and hypertension. RESULTS: As to the risk to high blood pressure and high systolic pressure, women with MM genotype were 7.7 (95% CI: 1.3-20.5) and 8.7 (95% CI: 1.8-20.1) times higher than those with TT genotype after adjustment for age and body mass index. Haplotype frequencies for M235T and G-6A were significantly different between hypertensive individuals and controls, which indicated an association of angiotensinogen gene haplotypes with hypertension, and a significant association of 235T/-6A haplotype with hypotensive effect. CONCLUSION: Our results suggest that angiotensinogen gene 235MM is a predictor for hypertension development in Tibetan women but not in men, and may exert its hypertensive effect on linkage disequilibrum with a possible function locus of G-6A.

Adult↗
PubMed2004

[Biotransformation of dehydroepiandrosterone by hairy root cultures of Anisodus tanguticus].

AIM: To modify the structure of dehydroepiandrosterone (DHEA). METHODS: Using hairy root cultures of Anisodus tanguticus to perform biotransformation of DHEA, using chromatographic and spectral techniques to isolate and identify the products. RESULTS: (1) The MS medium without plant hormone was suitable for the growth of the hairy root. (2) DHEA was converted into five products: androst-4-ene-3, 17-dione (I); 6alpha-hydroxyandrost-4-ene-3, 17-dione (II); 6alpha, 17beta-dihydroxyandrost-4-ene-3-one (III); androst-4-ene-3, 6, 17-trione (IV) and 17beta-hydroxyandrost-4-ene-3-one (V). CONCLUSION: It is the first time to use hairy root cultures of Anisodus tanguticus for the biotransformation of DHEA and five DHEA-related compounds were obtained.

Androstenedione↗