Search PubMed⌕ Search

Biomedical subjects

L Yu

Publications and source records attributed to L Yu.

At least 379 records · Page 21Linked to original sources
PubMed1998

[Reconstruction of transcriptional regulatory elements of human alpha-fetoprotein gene].

OBJECTIVE: To construct vectors that express therapeutic genes specifically in hepatocellular carcinoma, the TREs (Tissue-specific transcriptional regulatory elements) of natural human alpha-fetoprotein (AFP) was reconstructed. METHODS: Using subcloning techniques, the -870 bp(-)-3.06 kb fragment of the natural human AFP TREs was deleted to construct an artificial AFP(e/p) TREs which contains the "core" promoter and the -3.06 kb(-)-5.1 kb fragment of natural human AFP TREs that contains enhancer activity. RESULTS: By using chloramphenicol acetyltransferase (CAT) assay, the artificial AFP(e/p) TREs showed an activity 1.8 fold as high as that of the natural AFP TREs in an AFP positive human hepatocarcinoma cell line HepG2, and it also remained to be tissue-specific since there was no activity was detected in an AFP negative human larynxcarcinoma cell line Hep2. CONCLUSIONS: These results indicate that the artificial AFP(e/p) TREs we have constructed has higher activity than the natural AFP TREs and it also remains its hepatocarcinoma specificity. The reconstructed AFP(e/p) TREs is suitable for constructing of gene therapy vector with hepatocarcinoma expression specificity.

Carcinoma, Hepatocellular↗
PubMed1998

[On the best time for harvesting Dendrobium candidum Wall. ex Lindl].

OBJECTIVE: To explore the theory on the best time for harvesting Dendrobium candidum so that the production of the herb can be directed more effectively. METHOD: Based on a component analysis in combination with mathematical calculation, a synthetical appraisal on the yield, contents of effective components and efficacy of D. candidum in different growing periods has been made, and different appraisal indexes and synthetical harvesting indexes have been worked out. RESULT: The harvesting indexes from the first year to the fourth year are as follows: 5.69, 9.54, 17.9, 22.2 (curing throat and eye diseases); 11.2, 14.6, 21.6, 17.6(strengthening immunity); 8.44, 12.1, 19.7, 19.9(the above-mentioned indexes and yield factor considered together). CONCLUSION: The best time for harvesting D. candidum is in the fourth year for curing throat and eye diseases; in the third or first year for strengthening immunity; and in autumn of the third year if the above-mentioned indexes and yield factor are to be considered together.

Alkaloids↗
PubMed1998

[Radioimmunoimaging of bladder tumor with the intravesical administration of technetium -99m labelled monoclonal antibody].

OBJECTIVE: To make radioimmunoimaging of bladder tumor simple, safe and reliable. METHODS: Anti-human bladder carcinoma cell line BIU-87 monoclonal antibody-BDI-1 was labelled with technetium -99m by direct mercaptoethanol reducing method. RESULTS: The labelling rate was 69.6% and the radiochemistry pruity was higher than 95%. 33 patients received radioimmunoimaging of bladder tumor with the intravesical administration of technetium -99m labelled monoclonal antibody. The false positive rate was zero. 88.5% of all 29 bladder cancer patients had got positive immunoscintigraphy results, and 65.2% of them were confirmed by cystoscopic results. Both primary and recurrent tumor could be detected clearly and the smallest tumor detected was 0.5 cm in diameter. There were some differences between the radioimmunoimaging and cystoscopic results in 7 of 11 multitumor cases, which included tumor size, number and location. CONCLUSION: It is required to use more suitable isotopes and/or monoclonal antibodies to increase its sensitivity.

Administration, Intravesical↗
PubMed1998

[Apoptosis induced by ionizing radiation in TCC cell lines, EJ and BIU-87].

OBJECTIVE: To study the effect of ionizing radiation on the living status of TCC cell lines, EJ and BIU-87. METHODS: Different doses of X-ray were used on cell lines, EJ and BIU-87, and the cells were observed microscopically by fluorescent staining(EB and AO). RESULTS: The number of normal living cells declined and apoptotic as well as necrotic cells elevated with increase of radiation doses except for doses equal to or below 100 cGY, Apoptotic and necrotic cells increased as postradiation time delayed. CONCLUSION: The ionizing radiation may induce TCC apoptosis and necrosis.

Apoptosis↗
PubMed1998

[Retroviral-mediated transcriptional regulatory elements of alpha-fetoprotein gene directed specific expression of interleukin-2 in murine hepatoma].

OBJECTIVE: To target expression of interleukin-2 in alpha-fetoprotein (AFP) positive hepatocellular carcinoma. METHODS: A retroviral vector pDOR-mAFP-IL2 was constructed by coupling the transcriptional regulatory elements (TREs) of murine AFP gene with interleukin-2 cDNA in a retroviral vector. RESULTS: Subsequent to retroviral infection, expression of IL-2 could be detected in an AFP positive murine hepatoma cell line Hepa1-6 but not in psi 2, an AFP negative murine fibroblast cell line. CONCLUSIONS: Our results indicate that specific expression of IL-2 in hepatoma cell can be achieved by using of AFP TREs to control the expression of IL-2, and the retroviral vector which we have constructed may be used for further experimental studies on in vivo gene therapy.

Animals↗
PubMed1998

[A monoclonal antibody that reacts with an antigen on both normal and malignant prostate cells].

OBJECTIVE: To study the YDPC--a monoclonal antibody that reacts with an antigen on both normal and malignant prostate cell. METHOD: A murine monoclonal antibody (MAb) designated YDPC was generated by treating the primed spleen cells with leucine methyl ester (LeuOMe) following immunization of mice with prostate cancer cell line PC-3M. RESULT: YDPC reacted uniformly with all adenocarcinomas of the prostate examined. It also reacted with the surface antigen on normal prostate epithelial cells and on cells from benign prostate hyperplasia. YDPC reacted with a limited number of normal tissues including renal tubules, adrenal and sweat gland. In addition, three lymph nodes metastasis and one bladder metastasis were found to be strongly positive, while four transitional cell carcinomas of the prostate negative. Preliminary experiments showed that this antibody does specifically localize to prostate cancer xenografts in nude mice. CONCLUSION: YDPC reacts with a differentiation antigen and this antigen continues to be expressed on all adenocarcinomas of the prostate. This antibody may be useful in the diagnosis of or therapy for prostate cancer.

Adenocarcinoma↗
PubMed1998

[Apoptosis of renal cell carcinoma and apoptotic related genes bcl-2 and bax].

OBJECTIVE: To explore the mechanism of renal cell carcinoma (RCC). METHOD: We detected the apoptotic status and the expression of apoptotic related gene bcl-2 and bax protein in 48 cases of RCC with TdT-mediated dUTP-biotin nick end labeling (TUNEL) and immunohistochemistry methods. RESULT: 22 cases showed low expression of bcl-2 protein with an average apoptotic index (AI) of 1.35 and 26 cases had high expression of bcl-2 with an AI of 1.04 (P < 0.05). 34 cases showed low expression of bax protein with average AI of 1.03 and 14 cases had high expression of bax protein with an average AI of 1.63 (P < 0.01). The stronger bcl-2 expression, the weaker bax expression and the less number of apoptotic cells. CONCLUSION: both bcl-2 and bax take part in the occurrence and progression of RCC.

Adolescent↗
PubMed1998

[Expression and significance of Fas/APO-1 and bcl-2 protein in renal cell carcinoma].

OBJECTIVE: To investigate the role of Fas/APO-1 and bcl-2 in occurrence and progression of renal cell carcinoma. METHOD: Immunohistochemistry method was used to detect the expression of Fas/APO-1 and bcl-2 protein in 35 cases of renal cell carcinoma tissues and 26 cases of normal renal tissues. RESULT: The expression rate of Fas/APO-1 protein in renal cell carcinoma tissues was 57.14%, significantly lower than that in normal renal tissues (84.62%) (P < 0.05), and the intensity of expression was also lower. The expression rate of bcl-2 protein reached 80.00%, much higher than that in normal renal tissues (53.85%) (P < 0.05). CONCLUSION: Both Fas/APO-1 and bcl-2 take part in the occurrence and progression of renal cell carcinoma.

Adult↗
PubMed1998

[A limonoid from the Chinese drug dong-feng-jie (Atalantia buxifolia)].

A new limonoid was isolated from the ethanol extract of dried roots and stems of Atalantia buxifolia (Poir) Oliv.. Based on chemical properties and spectral analysis, including 1H- and 13CNMR, DEPT, MS, IR and UV spectra, its structure have been identified as: 6-deoxy-6 alpha-acetoxyatalantin acetate. This compound was isolated from this plant for the first time.

Drugs, Chinese Herbal↗
PubMed1998

[Assignment of a novel zinc finger gene ZNF191 to human chromosome 18Q12.1 by human/rodent somatic cell hybrid panel and fluorescent in situ hybridization].

A novel human zinc finger gene, ZNF191, was assigned to chromosome 18 by hybridization of human/rodent hybrid cell panel to a full-length cDNA as a probe. Meanwhile, a human genomic DNA lambda/DASH library was screened using this cDNA probe and several positive clones were obtained. Fluorescence in situ hybridization (FISH) was performed by using one of these positive clones, 16-1, as a probe. Thus, the ZNF191 gene was precisely mapped in 18q12. 1. To date, some hereditary diseases and tumors have been found to be associated with this region by analysis of genetic linkage and loss of heterozygosity. Hence, it suggested that the gene ZNF191 can be taken as a candidate gene responsible for those diseases and tumors.

Chromosome Mapping↗
PubMed1998

[Studies on pyridonecarboxylic acids as antibacterial agents. XIV. Synthesis and structure-activity relationships of 7,8-disubstituted-1-cyclopropyl-6-methyl-1,4-dihydro-4-oxo-3-quinoline carboxylic acids].

Eighteen pyridonecarboxylic acids, characterized by a methyl group at the C6-position instead of the usual fluorine atom, cyclopropyl at the N1-position, substituted amino groups at the C7-position, and some substituted groups (hydrogen, chlorine, nitro and amino) at the C8-position, were synthesized. The in vitro antibacterial activity of these compounds were tested, and the structure-activity relationships were also discussed. The results of the study showed that the activity of compounds 22 and 24 were less potent than that of ciprofloxacin against S. aureus, S. epidermidis, E. coli and P. aeruginosa, while they were 2-100 times more potent than ciprofloxacin against K. pneumoniae, S. marcescens, A. calcoacetous, E. aerogenes, S. typhi and S. typhimurium.

Anti-Infective Agents↗
PubMed1998

[Isolation of novel expression sequences of C2H2 type zinc finger protein gene from human brain tissue according to the conservation of zinc finger motif].

By low stringency PCR amplification of genomic DNA using the primers designed based on the conservation of zinc finger motif, we got 8 gradient eletrophoretic bands. After recovery of the second and third bands, the DNA fragments in them were cloned and sequenced. Compared to the GenBank database, among these 60 segments containing zinc finger motif, 23 segments were novel zinc finger genes' genomic segments. Then the human brain tissue cDNA library was screened, using these segments as probes, and 44 positive clones were obtained. Rescreening 28 of them, we got 20 rescreened clones. All of them were sequenced and sent to the GenBank DNA database for sequence analysis, the results showed that 16 were novel C2H2 type zinc finger protein cDNA segments. The cDNA segments encoding the novel C2H2 type zinc finger proteins provide the basic materials for cloning of full length cDNA of valuable novel zinc finger protein genes.

Amino Acid Sequence↗
PubMed1998

[Expression characteristic of Bacillus thuringiensis cry1 gene in Pseudomonas fluorescens Pfx-18].

The plasmids of lepidopteran-specific Bacillus thuringiensis strain from our laboratory were hybridized with RNA probe of cry 1Aa EcoR I-F fragment labelled using DIG. Cry1 gene was located in 39.3 MD plasmid. The plasmid was digested with Hind III and analysed by southern blot. It appeared both 7.1 kb and of 6.5 kb positive bands. The 7.1 kb fragment was ligated to broad-host-range vector pSUP106 and transformed into Pseudomonas fluorescens Pfx-18. The cloned strain, LZP-1 was obtained. The plasmids of LZP-1 were analysed by PCR. The results showed that gene-type is cry1Ab. SDS-PAGE analysis demonstrated that LZP-1 could express 66 kD insecticidal crystal protein and some small molecular weight peptides. Bioassay showed that motality of 1000-fold diluted fermentation broth was 33% to 3rd instar plulella xyloslelly larvae.

Animals↗
PubMed1998

[FTIR-PAS of rare earth coordinated compounds of Schiff base derived from vanillin and p-toluidine].

The Fourier transform infrared photoacoustic spectra (FTIR-PAS) of Schiff base derived from vanillin (3-methoxy-4-hydroxybenzaldehyde) and p-toluidine and its rare earth coordinated compounds in the 3800-200cm(-1) were measured and inverstigated. The coordinated compounds have two classes: [LnL2Cl x 3H2O]Cl2(Ln:La,Ce,Pr,Nd,Sm,Eu,Gd,Dy;L:Schiff base ligand) and [LnL2Cl2 x 2H2O] Cl x H2O(Ln:Ho,Er,Tm,Yb,Lu). In the coordinated compounds there is intermolecular hydrogen bond derived from phenolic hydroxy group. The bands at 400 and 300cm(-1) are respectively assigned to bonds M-O (water) and M-N.

Benzaldehydes↗
PubMed1998

Increased circulating levels of soluble HLA class I heterodimers in patients with sickle cell disease.

This study examined the presence of a persistent state of low-grade inflammation in sickle cell anemia patients by measuring circulating sHLA-I heterodimers and C-reactive protein during the steady state and after recent crises. Thirty-nine pediatric sickle hemoglobinopathy patients were studied during the steady state and 11 patients were evaluated within 1 month of a painful crisis. A disease severity score was generated for each patient, and soluble HLA-I (sHLA-I) and C-reactive protein levels were determined. Soluble HLA-I was significantly elevated in 55% of the steady-state group and in 36% of the recent-crisis group. The percentage of patients with elevated sHLA-I differed in the various disease subgroups in the steady state: 46% of Hb SS patients, 70% of Hb SC patients, 75% of Hb S beta-thal patients, and 20% of Hb SSF patients. Steady-state and recent-crisis sHLA-I levels were not significantly different. C-reactive protein levels were elevated in 11% of steady-state patients and in 9% of recent-crisis patients. Soluble HLA-I levels did not correlate with C-reactive protein levels or disease severity score, age, hemoglobin, reticulocyte count, platelet count, or white cell count. These results show that the majority of sickle hemoglobinopathy patients have elevated sHLA-I levels during the steady state and after recent crisis, suggesting the presence of chronic inflammation during the steady state.

Anemia, Sickle Cell↗
PubMed1998

Mechanisms of lysophosphatidylcholine-induced increase in intracellular calcium in rat cardiomyocytes.

Previous reports have demonstrated that lysophosphatidylcholine (LPC) increases the intracellular concentration of calcium ([Ca++]i) in the heart; however, the mechanisms responsible for this increase are not clear. We examined the effect of exogenous LPC on [Ca++]i in freshly isolated cardiomyocytes from adult rats. Our results showed that LPC elevated the [Ca++]i in a dose-dependent (2.5-10 microM) manner. The LPC (10 microM)-induced increase in [Ca++]i was augmented upon increasing the concentration of extracellular Ca++ and was abolished by the removal of Ca++ from the medium. Preincubation of cardiomyocytes with sarcolemmal L-type Ca++ channel blocker, verapamil, did not affect the LPC-evoked increase in [Ca++]i significantly. On the other hand, ouabain, a Na(+)-K+ ATPase inhibitor, and low concentrations of extracellular Na+ enhanced the LPC response. The LPC-induced increase in [Ca++]i was attenuated significantly by the inhibitors of Na(+)-Ca++ exchanger such as Ni++ and amiloride. Depletion of the sarcoplasmic reticulum (SR) Ca++ stores by low micromolar concentrations of ryanodine (a SR Ca(++)-release channel activator) or by thapsigargin (a SR Ca(++)-pump ATPase inhibitor) depressed the LPC-mediated increase in [Ca++]i. Combined blockade of Na(+)-Ca++ exchanger and inhibition of SR Ca(++)-pump or ryanodine receptor had an additive effect on the LPC response. These observations suggest that the increase in [Ca++]i induced by LPC depends on both Ca(++)-influx from the extracellular space and Ca(++)-release from the SR stores. Furthermore, Na(+)-Ca++ exchange plays a critical role in the LPC-mediated entry of Ca++ into cardiomyocytes.

Amiloride↗
PubMed1998

Dynorphin A as a potential endogenous ligand for four members of the opioid receptor gene family.

Dynorphin A is an endogenous opioid peptide that activates the kappa opioid receptor (KOR) with high potency. Some studies also showed that the distribution and functional activity of dynorphin A are not completely correlated with those of KOR, suggesting that dynorphin A may interact with other receptors. To investigate the possibility that dynorphin A may serve as an agonist for other opioid receptors, we took the advantage of the cloning of the three major types of opioid receptors, mu (MOR), delta (DOR) and KOR, and examined their affinity for and their activation by dynorphin A. We used mammalian cells transfected with each of the cDNA clones for the human receptors hMOR, hDOR, hKOR and showed that dynorphin A displaced [3H]-diprenorphine binding with Ki values in the nanomolar range at all three receptors. We also showed that, when hMOR, hDOR or hKOR was coexpressed with a G protein-activated potassium channel in Xenopus oocytes, dynorphin A induced a potassium current with EC50 values in the nanomolar range for all three receptors. Furthermore, we showed that the human hORLI, an opioid receptor-like receptor that has been identified as a novel member of the opioid receptor gene family, displayed dynorphin A binding and functional activation. These results indicate that dynorphin A is capable of binding to and functional activation of all members of the opioid receptor family, suggesting that, as a potential endogenous agonist, its activity in humans may involve interaction with other members of the opioid receptor family in addition to kappa receptors.

Animals↗