PubMed Health⌕ Search

Biomedical subjects

Y Liu

Publications and source records attributed to Y Liu.

At least 667 records · Page 37Linked to original sources
PubMed2001

[Screening and characterization of human phage antibody to hepatitis virus C NS5A antigen].

OBJECTIVE: To screen and characterize human phage antibody against hepatitis C virus (HCV)NS5A antigen. METHODS: The recombinant phages were panned by recombinant HCV NS5A antigen which was coated in a microtiter plate; after five rounds of biopanning, 35 clones were obtained and demonstrated specific to NS5A antigen. The specific binding capacity of the ScFv antibody to HCV NS5A antigen was determined by ELISA. RESULTS: HCV NS5A phage antibody had a specific combination capacity with hepatitis C virus NS5A antigen. The DNA sequence data showed that the ScFv gene was composed of 789 bp and codes for a peptide of 262 amino acid residues. CONCLUSIONS: Human single chain antibody to hepatitis C virus NS5A antigen has been identified by means of the phage display technology.

Antibodies, Viral↗
PubMed2001

[A study on the relationship between postmortem interval and the changes of DNA content in the kidney cellule of rat].

OBJECTIVE: To study changes of DNA content in the kidney cellule of rats and relationship with the postmortem interval. METHODS: This experiment chose seven parameter of cell nuclear, including the area and integral optical density, determined the changes of DNA content in the kidney cellule of 15 rats at different intervals between 0 and 48 h postmortem with auto-TV-image system. RESULTS: The degradation rate of DNA in nuclear has a certainty relationship to early PMI(in 48 h) of rat, and get binomial regress equation. CONCLUSION: Determining the quantity of DNA in nuclear should be an objective and exact way to estimate the PMI.

Animals↗
PubMed2001

[Histopathological observation of experimental slight viral myocarditis].

To study the diagnostic method of slight viral myocarditis in the field of forensic pathology, slight viral myocarditis model was induced in Balb/c murine by coxsackie virus B3. Organs of hearts, livers, spleens, lungs and kidneys were examined through routine pathological methods. Pathological changes at different levels of these organs were observed. The results indicated that viral myocarditis was a kind of disease with multiple organ alterations and that the pathological observation and comprehensive analysis of multiple organs was one of the useful methods for diagnosing slight viral myocarditis.

Animals↗
PubMed2001

[The paraoxonase Gln-Arg192 polymorphism in patients with coronary heart disease in Chinese population].

OBJECTIVE: To investigate the 192 Gln-Arg polymorphism of paraoxonase (PON) gene and its relationship with serum lipids levels in patients with coronary heart disease in Chinese population. METHODS: The genotype and allele frequency of paraoxonase gene 192 Gln-Arg polymorphism was assayed by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP). Serum lipids were measured by enzymatic kits in 118 CHD patients and 128 healthy subjects whose fasting serum TG levels were < 1.82 mmol/L and TC levels < 6.2 mmol/L from a population of Chinese Han nationality in Chengdu area. RESULTS: Both in CHD group and control group, the QR genotype of PON gene was the major one, and its frequencies were 0.578 and 0.525 respectively. No differences were found in PON gene Gln-Arg polymophism in the CHD group when compared with the control group. The frequency of R allele of PON gene in Chinese was significant higher than that in European and American Caucasians (0.51 vs. 0.26-0.31, P < 0.01) and Indian (0.51 vs. 0.17, P < 0.01), and significantly lower than that in Japanese (0.51 vs. 0.65, P < 0.01). CONCLUSION: These results suggested that the Gln-Arg192 polymorphism of the PON1 gene was not associated with coronary heart disease in Chinese population.

Aged↗
PubMed2001

[Serum apolipoprotein A I, B100 and E levels and apolipoprotein E polymorphism in patients with Alzheimer's disease and multiple infarction dementia in Chinese population].

OBJECTIVE: To investigate the relationship of serum apolipoprotein (apo) A I, B100 and E levels and apo E polymorphism to Alzheimer's disease (AD) and multiple infarction dementia (MID) in Chinese population. METHODS: The apoE phenotypes were assayed by isoelectric focusing and immunoblotting, and apolipoproteins were determined by radial immunodiffusion assay in 75 patients with AD, 36 patients with MID and 60 control subjects. RESULTS: The frequency of apo E4 allele (epsilon 4) was significantly higher and the frequency of epsilon 2 allele was lower in AD group, compared with those in the control group (0.2333 vs 0.0666, 0.0467 vs 0.0833, P < 0.05). The frequency of epsilon 4 allele in MID group was also higher than that in the control group (0.2083 vs 0.0666, P < 0.05). The fasting serum apoA 1 and E levels in AD and MID groups were remarkably lower than those in the control group (P < 0.001 and P < 0.05). CONCLUSION: Apo E4 allele epsilon 4 was associated with AD and MID. ApoE4 might be a risk factor for AD and MID, and apo E2 might be a protective factor for AD. The serum apo A I and apoE levels were significantly decreased in patients with Alzheimer's disease and multiple infarction dementia.

Aged↗
PubMed2001

[The levels of angiotensin and aldosterone in gases of hyperthyroid Graves' disease with and without hypokalemic periodic paralysis].

OBJECTIVE: To investigate the relationships between the changes of plasma angiotensin I (AT I). Angiotensin II (AT II). serum aldosterone (Ald) levels and hypokalemic periodic paralysis (THPP) complicating hyperthyroid Graves' disease. METHODS: The levels of serum potassium, TT3, TT4, FT3, FT4, Ald and the plasma AT I, AT II and 24 hours urine potassium output were determined in 73 cases of hyperthroid Graves' disease, of which 43 were complicated by THPP and the other 30 were grouped as NTHPP cases. RESULTS: The mean level of serum potassium in THPP group was significantly lower than that in NTHPP group (P = 0.000), and the mean level of 24 hours urine potassium output in THPP group was significantly higher than that in NTHPP group(P = 0.000); The mean levels of plasma AT II and serum Ald in THPP group in upright position were significantly higher than those in NTHPP group (P = 0.008 and 0.013, respectively). The mean levels of 24 hours urine potassium output, plasma AT II and serum Ald in upright position were negatively correlated to serum potassium in both groups. The level of serum Ald in upright position was positively correlated to the level of 24 hours urine potassium out-put. The mean levels of plasma AT I and AT II in supine position were positively correlated to serum T3, and the level of plasma AT II in upright position was positively correlated to serum FT3. CONCLUSION: The level of 24 hours urine potassium output rises in THPP patients; the high levels of AT and Ald may contribute to the pathogenesis of the disease.

Adult↗
PubMed2001

[A study on transmission of pathogenic bacteria of rampant caries from mothers to children].

OBJECTIVE: In order to prevent rampant caries in children, the transmission from mothers to children of pathogenic bacteria of rampant caries will be investigated in this study. METHODS: By using fingerprint technique, the genetic diversities of Streptococcus mutans(S. mutans) were examined respectively in 10 children with rampant caries, 10 children without rampant caries S. mutans, 10 2-year-old caries-free children, and their mothers. The levels of S. mutans in saliva of mothers were also examined. For fingerprinting, chromosomal DNA of isolates obtained from plaques of these children and from saliva of their mothers were digested with restriction endonuclease HindIII and examined by electrophoresis on 0.7% agarose gel. DNA fingerprints were obtained and analyzed for genotypic similarities. RESULTS: The DNA fingerprint patterns showed that the proportion of children whose genotypes of S. mutans matched their mothers in the children with rampant caries was 70%, which is similar to that in the children without rampant caries and the caries-free children (60% respectively). The number of distinct genotypes of S. mutans harbored in children with rampant caries was, on average, greater than the number of genotypes present in children without rampant caries and caries-free children (1.7, 1.2 and 1.1 respectively, P < 0.05). Mothers of children with rampant caries had similar levels of S. mutans in saliva as those mothers of children without rampant caries and caries-free children. However, mothers of children with rampant caries had significantly higher DMFT scores and higher levels of Streptococcus sobrinus (S. sobrinus) in saliva than the mothers of caries-free children did. CONCLUSION: In all child groups, mothers were probably the main source of infection with S. mutans. Rampant caries in children is associated with DMFT scores and levels of S. sobrinus in saliva of mothers. In the initiation of rampant caries experienced by a child, the transmission of pathogenic bacteria from mothers to children may be the main source.

Adult↗
PubMed2001

[The isolation and identification of pathogenic bacteria from rampant caries in children].

OBJECTIVE: In order to prevent rampant caries in children, the predominant pathogenic bacteria of rampant caries in children were defined. METHODS: The pathogenic bacteria of rampant caries were isolated and identified in 30 children with rampant caries, aged from 2 to 5 years old. Samples were collected from the caries of labial surfaces of maxillary anterior deciduous teeth, including caries lesions and caries-free smooth enamel surfaces. Plaque were obtained from the cervical third areas of the maxillary labial anterior deciduous tooth surfaces in children without rampant caries and caries-free children and served as controls respectively. The isolates were identified by colony morphology, biochemical tests and DNA base contents (mol percent G + C). RESULTS: The prevalence of Streptococcus mutans (S. mutans) and Streptococcus sobrinus (S. sobrinus) in the plaque of caries lesions and the proportions of S. mutans and S. sobrinus in the plaque of 2 sampling sites of children with rampant caries were all significantly higher than those of children without rampant caries and caries-free children (P < 0.05). CONCLUSION: S. mutans and S. sobrinus are predominant pathogenic bacteria in rampant caries in children.

Child↗
PubMed2001

[Antibacterial activities of seven commonly used antibiotics to 106 isolated strains of porphyromonas gingivalis in vitro].

OBJECTIVE: Porphyromonas gingivalis (Pg) is one of the main putative pathogens of periodontal disease, especially of adult periodontitis. This in vitro study was aimed at observing the inhibitory activities of 7 commonly used antimicrobical drugs on 106 stains of Pg which isolated from subgingival plaques of sites with adult periodontits. METHODS: Kirby-Bauer paper disk method was used in this study. RESULTS: Pg was highly susceptible to Clindamycin, Sulfamzthoxazole timethoprin, Tetracycline and Cefazolin, the susceptibility rates were 93.4%, 78.3%, 60.4% and 56.6% respectively. CONCLUSION: Majority of the strains of Pg was moderately susceptible to cefalexin and acetylspiramycin, while no strains of Pg was susceptible to Penicillin G. The concentrations of Pg solutions (10(5) CFU/ml, 10(6) CFU/ml and 10(8) CFU/ml) had not influence on the results. This data is helpful for clinically antibiotic selection of periodontal treatment.

Adult↗
PubMed2001

[The clinical investigation of bacteriology of chronic suppurative otitis media].

OBJECTIVE: To understand bacteriology of chronic suppurative otitis media (CSOM) and drug sensitivity of isolated bacteria for better treatment of CSOM. METHOD: Secretions of 92 samples with chronic suppurative otitis media were collected and cultured for aerobic and anaerobic bacteria respectively. Drug sensitivity test of isolated bacteria was done. RESULT: Aerobic bacteria was found in 75 of 92 samples (81.5%), the main pathogens were pseudomonas aeruginosa, aureus staphylococcus and bacillus proteus, and their sensitive rates for ciprofloxacin were 89.0%, 88.2% and 85.0% respectively. Anaerobic bacteria was found in 10 samples (10.9%) and the relative sensitive drug was cefoperazone sodium. CONCLUSION: Pseudomonas aeruginosa, aureus staphylococcus and bacillus proteus are the main pathogens of chronic suppurative otitis media, and their sensitive rates for ciprofloxacin are high.

Adolescent↗
PubMed2001

[Measurement of binding constants of metal complex by indirect ultraviolet affinity capillary electrophoresis].

The binding constants of complexes formed by metal ions and ligands have been obtained by affinity capillary electrophoresis, according to the measurement of the migration times of metal ions effected by ligands in aqueous media, under the experimental model named electrophoretic peak shifting. This method has been applied to the research of magnesium ion with citric acid and manganese ion with tartaric acid. Under the condition of imidazole and acetate buffer (pH 5.01) at 20 kV running voltage, the migration times of metal ion with ligand of different concentrations have been measured. The estimated logarithmic values of binding constants after computation were 3.27 for magnesium-citric acid and 2.28 for manganese-tartaric acid, which showed that the results were in agreement with the data in previous literature. This method is applicable to the measurement of the binding constants of complex systems with 1:1 ratio.

Chelating Agents↗
PubMed2001

[Comparison of the post-operative complication in head-neck malignant neoplasms between aged and pre-aged].

OBJECTIVE: To compare the post-operation complication of head-neck malignant tumor in the aged with pre-aged. METHOD: 80 aged and 92 pre-aged cases of head-neck tumor were performed operation. In the aged group, 26 cases were performed with preoperative radiotherapy and 13 cases with postoperative radiotherapy. In the pre-aged group, 40 cases were performed with preoperative radiotherapy and 6 cases with postoperative radiotherapy. RESULT: The incidence of complication in the aged is higher than that in the pre-aged group. Moreover, the post-surgery complications of tumor in head and neck in the aged preferably appear in the cardiopulmones and urology. In contrast, most of the complication in the pre-aged appears in the incision of operation. CONCLUSION: Prior to surgery, we should clear with the situation of patients, and consequently choose appropriate methods of operation. Age does not play an essential role in the decision of the methods of operation.

Age Factors↗
PubMed2001

[Preparation and evaluation of amide-octyl-bonded phase for the separation of basic substances in reversed-phase liquid chromatography].

A new bonded-phase, amide-octyl-bonded phase (AOBP), with an internal polar functional group-amide was firstly prepared in domestic by two-step reaction process. The amino phase was formed in the first step and further modified in the second step by attaching an alkyl chain via reaction of an acid chloride with the amino ligand. Characterization of prepared packing was carried out with elemental analysis and Fourier transform infrared (FTIR) spectrometry. Hydrophobicity, selectivity and silanophilic activity of AOBP were evaluated by using organic components including acidic, bascic and neutral analytes and methanol-water as binary mobile phase. The applicable ranges of pH and stability of AOBP were also evaluated. The results showed that AOBP has excellent chromatographic properties and resistance to hydrolysis between pH = 2.5-7.5, It can be used for the separation of basic solutes efficiently.

1-Octanol↗
PubMed2001

[The clone and comparison of very virulent plus Marek's disease virus(vv+ DMV)648 strain glycoprotein E(gE) gene].

The glycoprotein E(gE) gene of very virulent plus Marek's Disease (vv+ MDV) 648 strain was amplified by polymerase chain reaction (PCR) and cloned into pUC18 vector. The gE sequence was determined and analysed. The whole length of 648 strain gE gene is 1494 base pairs. The protein encoded by gE gene has several features characteristic of a membrane-associated glycoprotein. It contains eight potential glycosylation sites, a markedly hydrophobic region at the N terminus that could function as a signal peptide and a hydrophobic segment (aa 391-419) at C terminus that could function as a transmembrane anchor element. Comparison of the gE between 648 strain and virulent MDV (vMDV) GA strain revealed that gE sequence is conserved in MDV serotype 1, there are only two basepairs different, (at bp 512 and 1472), which induce two amino acids changed respectively (at aa 171 and 491). The function of 648 strain gE and the difference of gE between 648 strain and GA strain is on study.

Amino Acid Sequence↗
PubMed2001

[Studies on transference of hydrogenase genes of Rhizobium arachis].

The hydrogen-uptake genes were transferred into wild Rhizobium arachis Ra strains (Hup-, Nif+, Apr) by triparental mating using pRK2013 as help plasmid. A transconjugant R. arachis Rz34-2(Hup+, Nif+, Apr, Tcr) which expressed high activities of hydrogenase and nitrogenase under free-living and symbiotic state was screened. Peanut inoculation test with recipient R. arachis Ra34, transcojugant Rz34-2 and control strain R. arachis L8-3 (Hup+, Nif+) was carried out respectively. The results showed that, compare to treatment without inoculation, inoculation with R. arachis Ra34 and R. arachis L8-3, the dry weight of leaf inoculated with transconjuant Rz34-2 increased 6.2%, 7.6% and 6.3% respectively; the N-content of seed increased 8.8%, 10.0% and 6.0%; the output increased 18.8%, 10.5% and 10.7%. This suggested that legume plants inoculated with Rhizobium strains (Hup+) were more efficient to accumulate N and to increase its output.

Arachis↗
PubMed2001

[Effect of microgravity simulation with clinostat on different strains in Anabaena oryza].

The Biological responses of Anabana oryza (different strains) to microgravity simulation with clinostat were analyzed. The simulation of growth rate was observed under clinoration all the strains, especially in flight strains (AoR16 and AoSR16-17). Anabana oryza HB23 showed higher activity than flight strains in photosynthesis and respiration. The nitrogen which flight strains with high nitrogrnase activity fixed under culturing in ground was used to accumulate phycobiliprotein in cell and excrete ammonium out of cell after meeting the normal metabolism, however, it was mainly used to simulate growth rate under culturing with clinostat. menwhile, it was different from space flight that microgravity simulation with clinostat was not able to induced the phenotype segregation in Anabana oryzae.

Anabaena↗
PubMed2001

[Study on the form and stability of alpha and beta domain of metallothionein binding to lead (II)].

For studying the actions of metallothionein(MT) binding to lead, the alpha and beta structural domain of metallothionein binding to Cd (Cd7-alpha-MT and Cd7-beta-MT) was extracted and purified from a strain of BL2I by dissolving them in acid to eliminate protein. The apo-alpha-MT and apo-beta-MT were separated by gel Sephadex-G25 to eliminate Cd. Different doses of lead were added to the apo-alpha-MT and apo-beta-MT. The structure of MT metal Cluster with lead was formed after reacting completely, and was then examined by ultraviolet spectrophotometer. The UV spectrum showed that the interaction of lead with alpha domain leading to two kind of products, one binding with 4 lead(Pb4-alpha-MT) and the other binding with 7 lead (Pb7-alpha-MT). Only one product, the beta domain binding with 3 lead(Pb3-beta-MT) was formed. The reaction rate of these products with DTNB was also measured in this study. Results showed that the domain binding to 4 lead was more stable than the others. All these works provide strong evidence that further studies on the mechanism of MT interacting with lead and the function of MT in eliminating lead were needed.

Drug Interactions↗