Search PubMed⌕ Search

Biomedical subjects

L Yu

Publications and source records attributed to L Yu.

At least 307 records · Page 17Linked to original sources
PubMed1999

[Isolating candidate inserted fragment from positive fused phage clones using quantitative PCR].

OBJECTIVE: To isolate quickly and exactly the specific inserted fragment from fused phage clones which were obtained from cDNA library by hybridization. METHODS: According to the amplification principle of quantitative polymerase chain reaction (PCR) and based on the difference of original template quantity,target cDNA fragment was isolated and identified by two PCRs. RESULTS: A positive clone with specific cDNA fragment of HumGT-H1 gene was obtained from a two-phage fused clone by using this method,and the inserted fragment was verified to be the 5' cDNA sequence of HumGT-H1,1.9kb in length. So another hybridization screening is not necessary. CONCLUSION: The method presented is effective and rapid in gene cloning and can greatly save time and materials.

Bacteriophages↗
PubMed1999

[Detection of numerical chromosomal aberrations in epididymal sperm of mice using three-color FISH with chromosome-specific DNA probes].

To detect malsegregation of chromosomes during meiosis in male mice, three-color FISH using DNA probes specific for mouse chromosomes X, Y and 8 was performed on epididymal sperm decondensed for 30 min each in 10 mmol/L DTT and 4 mmol/L LIS, and conventional chromosome counting was also carried out on C-banded MMII cells. Comparisons between these two methods indicate as the following: (1) three-color FISH is a simple, rapid and sensitive approach; (2) The estimate of the frequency of aneuploidy obtained from three-color FISH analysis is more reliable since extremely large numbers of sperm (more than 10,000 sperm per animal) are scored; (3) The rates of cells arrested at meiosis I and meiosis II (representing diploid sperm) can be detected only by using the three-color FISH approach; (4) Malsegregation of chromosomes occurred during both meiosis I and meiosis II can be detected simultaneously by using this new approach. The probes and scoring criteria used in FISH on interphase sperm nuclei, and the necessity of using three or more chromosome-specific DNA probes to thoroughly evaluate aneugenic effects of factors tested on meiosis in male mice were discussed.

Animals↗
PubMed1999

A fast, sensitive and specific method for rice dwarf virus detection by northern blot hybridization.

Based on stability of double-stranded (ds) RNA, a new, fast, sensitive, and specific method for detection of genomic rice dwarf virus (RDV) dsRNA by molecular hybridization was developed. In contrary to the commonly used, standard Northern blot analysis, dsRNA is denatured in the immobilized state on the blot. Therefore, risk of degradation of single-stranded (ss) RNA by ribonuclease (RNase) during sample preparation, electrophoresis and blotting is eliminated. This method overcomes disadvantage of incomplete denaturation of dsRNA in Northern blot analysis. In conclusion, the newly developed method is reliable, sensitive, very specific, and gives a low background. The entire procedure is also less time consuming; it can be completed within 2-3 days. The new method may be regarded as a modification of the standard Northern blot analysis.

Blotting, Northern↗
PubMed1999

[Study on the methylation of p15 gene CpG islands in acute leukemia: using methylation-specific PCR method].

OBJECTIVE: To explore the feasibility of the methylation of p15 gene CpG islands as a common gene marker for all types of acute leukemias(AL). METHODS: The methylation of p15 gene CpG islands in bone marrow from 40 cases of newly diagnosed or relapsed AL, 5 cases of AL in CR and 8 of normal subjects was analyzed by using methylation-specific PCR methods(MSP), and the product of MSP was sequenced. RESULTS: p15 gene CpG islands were methylated in 80% (32/40) of the newly diagnosed or relapsed AL, no difference between AML and ALL was observed. One positive result was found in the 5 AL patients in CR and this patient soon relapsed. The bone marrow cells from 8 normal subjects did not have p15 gene CpG islands methylation, which suggested that such methylation was peculiar to AL cells. DNA sequencing confirmed the right expected sequence. The sensitivity of MSP was 10(-3). CONCLUSION: The methylation of p15 gene CpG islands occurs very commonly in every types of AL. It can be used as a gene marker for ALs and for minimal residual disease in CR. MSP needs neither special methylation-sensitive restricted sites, nor high volume of DNA. There is no radioactive pollution, and the sample need not be fresh. MSP is a very sensitive, simple and specific method for the detection of DNA methylation.

Acute Disease↗
PubMed1999

[The value of "blood vessel convergency" sign in the diagnosis of small peripheral lung cancer].

OBJECTIVE: To evaluate blood vessel convergency (BVC) sign in the radiologic diagnosis of small peripheral lung cancer. METHODS: A prospective thin-section CT-pathology comparative study was done in 123 cases with solitary pulmonary nodules less than 3 cm in diameter including 83 peripheral lung cancera (adenocarcinoma 46, squamous-cell carcinoma 21, bronchiolo-alveolar-cell carcinomas 7, undifferentiated carcinoma 6, adenosquamous carcinoma 3) and 40 benign lesions. They were pathologically and clinically confirmed. Serial transverse sections of the surgically resected specimens were examined microscopically in 91 cases. Attention was focused on the imaging and histological manifestations of BVC. RESULTS: BVC was found in 54 (65.1%) peripheral lung cancers and in 8(20%) benign nodules (chi 2 = 22.75, P < 0.001). Histologically, the convergent vessels were shown to be dilated arterioles or venules. CONCLUSION: Blood vessel convergency can be regarded as a valuable sign for the diagnosis of small peripheral lung cancers.

Adult↗
PubMed1999

[Effect of dingxin recipe on arrhythmia and injury induced by ischemia and reperfusion in rabbits].

OBJECTIVE: To investigate the protective effect of Dingxin Recipe (DXR) on arrhythmia and injury induced by ischemia and reperfusion. METHODS: Rabbits were randomly divided into four groups and administered orally with DXR of high dose, low dose, propanolol and distilled water. Two-step coronary artery ligature was used to form ischemia and reperfusion model. Superoxide dismutase (SOD), cyclic adenosine monophosphate (cAMP), norepinephrine (NE), dopamine (DA), 5-hydroxytryptamine (5-HT), myocyte ultrastructural injury and occurrence of arrhythmia were investigated. RESULTS: DXR could obviously antagonize arrhythmia induced by myocardial infarction or ischemia and reperfusion in rabbits. Compared with the control group, DXR of high and low doses could improve the changes in ST-T. In rabbits treated with DXR, the levels of SOD were elevated while cAMP, NE, DA, 5-HT and the whole blood viscosity were lowered. CONCLUSIONS: DXR could obviously antagonize arrhythmia and injury induced by ischemia and reperfusion, DXR may clear oxygen free radical, regulate the second messenger, inhibit sympathetic nerve system, improve local circulation, protect mitochondria and prevent the activation of lysosome and safeguard the cardiac myocyte to be free from injury.

Animals↗
PubMed1999

[Changes of serum elastase, alpha 1-antitrypsin, procollagen III peptide and malonaldehyde in smokers with and without chronic obstructive pulmonary diseases].

OBJECTIVE: Serum elastase, alpha(1)-antitrypsin (alpha(1)-AT), procollagen III peptide (PIIIP) and malonaldehyde (MDA) were studied in smokers with and without chronic obstructive pulmonary disease (COPD) to explore the roles of these factors in COPD induced by smoking. METHODS: A design of 154-pair case-control study was used. alpha(1)-AT, MDA and PIIIP were determined with colorimetric method, fluo-spectrophotometric method and radio-immunological assay, respectively, in non-smoker control and smokers with and without COPD. RESULTS: Serum PIIIP content was increased in smokers and alpha(1)-AT decreased significantly in patients with COPD. CONCLUSION: Decreased alpha(1)-AT may be a susceptible factor in the development of COPD caused by smoking.

Adult↗
PubMed1999

[The clinical significance of lung resistance-related protein gene (lrp), multidrug resistance-associated protein gene (mrp) and mdr-1/p170 expression in acute leukemia].

OBJECTIVE: To evaluate the relationship between lrp, mrp, mdr-1/p170 and multidrug resistance in acute leukemia (AL). METHODS: 85 AL patients were divided into three groups: untreated (A), complete remission (B) and relapsed/refractory (C). The expression of lrp, mrp and mdr-1 mRNA was detected with RT-PCR assay and that of p170 measured with immunocytochemistry. RESULTS: The frequency of lrp gene expression in ANLL A, B and C group was 11.11%, 9.09% and 36.36%, in ALL A, B, C group it was 0%, 20.00% and 46.67%; the frequency of mrp gene expression in ANLL A, B, C group was 44.44%, 9.09% and 59.09%, in ALL A, B, C group it was 28.57%, 20.00% and 53. 33%; the frequency of mdr-1 gene expression in ANLL A, B, C group was 0%, 4.54% and 59.09%, in ALL A, B, C group it was 0%, 0% and 33.33%; p170 expression in ANLL C group was (9.45 +/- 14.66) %, it was the highest value in the three groups; statistics showed that there was no correlationship among the expressions of lrp, mrp and mdr-1 gene, P > 0.05; patients with lrp and mdr-1 expression had a lower complete remission (CR) percentage than those who had not in the untreated group; the combination of lrp, mrp and mdr-1 gene detection turned out to be a more sensitive, specific and accurate way in evaluation of multidrug resistance (MDR). CONCLUSION: Overexpression of one or more genes of lrp, mrp and mdr-1/p170 is associated with MDR in AL. Expression of lrp, mrp and mdr-1/p170 is good indicators in clinical MDR. Two or three factors of lrp, mrp and mdr-1 are more valuable in the evaluation of MDR than any one of these three factors. The mechanisms of mrp, lrp and mdr-1 causing MDR are different, it means that the mechanisms of MDR are complicated the combination of lrp, mrp and mdr-1/p170 detection may be the best way to evaluate MDR.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

[Dynamic monitoring of serum soluble HLA class I antigens in renal transplant recipients].

OBJECTIVE: To investigate the relations between serum soluble HLA class I antigens (sHLA-I) and the period of acute rejection and infection in renal transplant recipients. METHODS: We measured the serum levels of sHLA-I in 36 renal transplant recipients with ELISA dynamically. RESULTS: The serum sHAL-I levels were higher in uremia patients than in normal controls [(2.94 +/- 0.34) microg/L vs. (0.76 +/- 0.33) microg/L, P < 0.05]. After renal transplantation, the serum sHLA-I levels decreased significantly in stable patients [(0.63 +/- 0.33) microg/L], but increased significantly 3 days before acute rejection and 5 or 7 days after infection. CONCLUSIONS: The serum sHLA-I levels can be used as a parameter for monitoring acute rejection and infection in renal transplantation.

Adolescent↗
PubMed1999

[The normal value of DPOAE and effect of intensity differ of probe tone].

OBJECTIVE: To investigate the normal value of DPOAE and effect of intensity differ of probe tone. METHOD: 30 subjects (60 ears) age from 17 to 40 were examined in this article, and the amplitude of DPOAE were measured when using L1 = L2 = 70 dB SPL and L1 = 70 dB SPL, L2 = 65 dB SPL. RESULT: DPOAE was recorded in 100%. The amplitude of DPOAE when using L1 = 70 dB SPL, L2 = 65 dB SPL is larger than the amplitude of DPOAE when using L1 = L2 = 70 dB SPL. CONCLUSION: Those results give us useful information for clinic.

Acoustic Stimulation↗
PubMed1999

[Isolation and cloning of human beta 1, 4-galactosyltransferase III gene].

Using the conservative nucleotide sequences encoding the catalytic domain of the beta-1, 4-GalT genes in human, bovine, mouse, chick and snail as probes to search the NCBI GenBank EST database, several ESTs with high homology were obtained. Primers were designed in the flanking sequence of EST contig. Using the PCR product amplified in human placenta cDNA library as probe to perform "walking" hybridization with human placenta cDNA library, a cDNA fragment with the length of 1,907 bp was cloned. It contained an open reading frame (ORF) with the length of 1,179 bp, which encodes 393 amino acid residues. The deduced amino acid sequence of this gene shares 43.8% identity to the human beta-1, 4-GalTI and 60.9% in the catalytic domain especially. The expression mapping showed that it was expressed in human most tissues with a single 2.4 kb transcript, but the relative expression level of the transcript are vary. While this gene was mapped on chromosome 1 using the cDNA hybridization with human/rodent hybrid cell line DNA Southern blot panel.

Amino Acid Sequence↗
PubMed1999

[Determination of total sulfite in wine by high performance liquid chromatography(HPLC) with fluorescence detection].

A highly sensitive fluorometric method for the determination of total sulfite in wine is reported. The strong fluorescent derivatives formed by the quantitative reaction of sulfite in wine and N-(9-acridinyl) maleimide(NAM) in aqueous solution under mild conditions was injected into the HPLC. Separation was performed on an ODS column(200 mm x 5 mm) with a mobile phase of V(CH3CN):V(0.1 mo/L NH4AC) = 25:75 at a flow rate of 1.0 mL/min and detected by fluorometry at 455 nm(excitation at 365 nm). There was a good linear calibration curve in the range from 0.25-4 mg/L(r = 0.9998), The limit of detection was 1 ng. Sulfite mass concentration in wine has been determined by this method with good results and recoveries. This method is simple, rapid and reliable, and a sample size of only 1 mL is required to complete an analysis.

Chromatography, High Pressure Liquid↗
PubMed1999

[The submucosal structure of the endolymphatic sac of guinea pigs].

OBJECTIVE: To investigating the submucosal structure of the endolymphatic sac (ES), so as to analyse the role of ES in the function of inner ear. METHOD: The temporal bone of the guinea pigs were cleared in methyl salicylate and inspected under a stereomicroscope. The ultrastructure of endolymphatic sac has been observed by transmission electron microscope. RESULT: The extensive vascular system around the sac and has compact contact with sinus sigmoid. Its submucosal space comprises both arterioles and venules, as well as lymphatic sinus. CONCLUSION: The result suggests that the ES is a very metabolically active structure and has a pressure regulating function. The disturbance of endolymphatic resorptive function seems to result endolymphatic hydrops after the vascular supply poverty of endolymphtic sac. It's may be the causative factor of Meniere's disease.

Animals↗
PubMed1999

[Surface-enhanced Raman spectra studies on a novel dipyridophenazine complexes of ruthenium(II) and it's effect on DNA].

SERS is better method at analysing the samples which are prone to emit fluorescence or photodecomposition than other methods. Raman scattering of a novel complexes of Ruthenium (II): Ru(bpy)2dppz and it's effects on DNA were studied with surface-enhanced Raman spectra(SERS). We find that when this complex binds to DNA, only the ligand dppz intercalate into the double helix of DNA, and form a larger conjugate system, affect the metal-to-ligand charge transfer(MLCT), produce strong photoluminescence. All these cause shifting of some Raman peaks of the complex and changex of the relative intensity of some other peaks. And on the charge absorbed spectra, after the addition of DNA, the compex' absorbed peaks of Ru(bpy)2dppz solvent shift to long wavelength, this is also one of the character of the intercalation.

DNA↗
PubMed1999

[Analysis of the spectrum of solid sodium carboxyl in N+ ion implantation].

The changes in molecular structure of PhCOONa and CH3COONa samples in 25 keV N+ ions implantation were measured by UV-spectrum. The dose response of UV-absorption was deduced. It was found that a new compound with UV-absorption could be produced in implanted CH3COONa sample. The cyano-group could be produced in PhCOONa and CH3COONa samples implanted by the N+ ion beam.samples implanted by the N+ ion beam.

English Abstract↗
PubMed1999

Suppressed endothelin-1 production by FK506 and cyclosporin A in ischemia/reperfusion of rat small intestine.

BACKGROUND: Endothelin-1 (ET-1), a novel vasoconstrictor, possibly plays a role in the mediation of ischemia/reperfusion (I/R) injury. Tacrolimus (FK506) and cyclosporin A (CsA) were reported to maintain tissue microcirculation of the liver subjected to I/R. This study investigated the effects of these immunosuppressants on intestinal I/R in terms of intestinal tissue microcirculation associated with ET-1. METHODS AND RESULTS: Male S-D rats were pretreated twice with FK506 (0.2 mg/kg), CsA (10 mg/kg) or only saline solution (0.5 mL). The tissue microcirculation in the control was reduced after I/R (29% +/- 10%) accompanied by hypotension, increased tissue ET-1 expression (25.0% +/- 6.4% to 67.9% +/- 5.0% 60 minutes after reperfusion), and increased ET-1 level in the portal blood (3.4 +/- 0.9 to 23.6 +/- 6.1 pg/mL). FK506 suppressed ET-1 expression (27.3% +/- 5.2%, 4.1 +/- 2.2 pg/mL), maintained microcirculation (96% +/- 16%), and blood pressure, reduced histologic damage, and improved survival. CsA had a similar but weaker effect compared with FK506. An additional experiment was performed with BQ485Na (BQ), an ETA receptor antagonist, to evaluate the genuine role of ET-1. BQ showed almost the same effects as FK506. CONCLUSIONS: FK506 and CsA, particularly the former, maintain microcirculation and protect the tissue from I/R injury by suppressing the production and release of ET-1.

Animals↗
PubMed1998

Generation of superoxide anion by succinate-cytochrome c reductase from bovine heart mitochondria.

Production of superoxide anion (O-2), measured as the chemiluminescence of the 2-methyl-6-(p-methoxyphenyl)-3, 7-dihydroimidazo[1,2-a]pyrazin-3-one hydrochloride (MCLA)-O-2 adduct, was observed during electron transfer from succinate to cytochrome c by reconstituted succinate-cytochrome c reductase-phospholipid vesicles replenished with succinate dehydrogenase. Addition of carbonyl cyanide p-trifluoromethoxyphenylhydrazone or detergent to the reconstituted reductase-phospholipid vesicles abolished O-2 production, suggesting that O-2 generation is caused by the membrane potential generated during electron transfer through the cytochrome bc1 complex. Production of O-2 was also observed during electron transfer from succinate to cytochrome c by antimycin-treated reductase, in which approximately 99.7% of the reductase activity was inhibited. The rate of O-2 production was closely related to the rate of antimycin-insensitive cytochrome c reduction. Factors affecting antimycin-insensitive reduction of cytochrome c also affected O-2 production and vice versa. When the oxygen concentration in the system was decreased, the rate of O-2 production and cytochrome c reduction by antimycin-treated reductase decreased. When the concentrations of MCLA and cytochrome c were increased, the rate of O-2 production and cytochrome c reduction by antimycin-treated reductase increased. The rate of antimycin-insensitive cytochrome c reduction was sensitive to Qo site inhibitors such as 5-undecyl-6-hydroxy-4,7-dioxobenzothiazole. These results indicate that generation of O-2 during the oxidation of ubiquinol by the cytochrome bc1 complex results from a leakage of the second electron of ubiquinol from its Q cycle electron transfer pathway to interact with oxygen. The electron-leaking site is located at the reduced cytochrome b566 or ubisemiquinone of the Qo site because addition of MCLA to antimycin-treated cytochrome bc1 complex, in the presence of catalytic amounts of succinate-cytochrome c reductase, delayed cytochrome b reduction by succinate. In the presence of oxidized cytochrome c, purified succinate dehydrogenase also catalyzed oxidation of succinate to generate O-2. When succinate dehydrogenase was reconstituted with the bc1 particles to form succinate-cytochrome c reductase, the production of O-2 diminished. These results suggest that reduced FAD of succinate dehydrogenase is the electron donor for oxygen to produce O-2 in the absence of their immediate electron acceptor and in the presence of cytochrome c.

Animals↗