Biomedical subjects

Yan Liu

Publications and source records attributed to Yan Liu.

At least 127 records · Page 7Linked to original sources

PubMed2006

Detection of biomarkers with a multiplex quantitative proteomic platform in cerebrospinal fluid of patients with neurodegenerative disorders.

Biomarkers are needed to assist in the diagnosis and medical management of various neurodegenerative disorders, including Alzheimer's disease (AD), Parkinson's disease (PD), and dementia with Lewy body (DLB). We have employed a multiplex quantitative proteomics method, iTRAQ (isobaric Tagging for Relative and Absolute protein Quantification), in conjunction with multidimensional chromatography, followed by tandem mass spectrometry (MS/MS), to simultaneously measure relative changes in the proteome of cerebrospinal fluid (CSF) obtained from patients with AD, PD, and DLB compared to healthy controls. The diagnosis of AD and DLB was confirmed by autopsy, whereas the diagnosis of PD was based on clinical criteria. The proteomic findings showed quantitative changes in AD, PD, and DLB as compared to controls; among more than 1,500 identified CSF proteins, 136, 72, and 101 of the proteins displayed quantitative changes unique to AD, PD, and DLB, respectively. Eight unique proteins were confirmed by Western blot analysis, and the sensitivity at 95% specificity was calculated for each marker alone and in combination. Several panels of unique makers were capable of distinguishing AD, PD and DLB patients from each other as well as from controls with high sensitivity at 95% specificity. Although these preliminary findings must be validated in a larger and different population of patients, they suggest that a roster of proteins may be generated and developed into specific biomarkers that could eventually assist in clinical diagnosis and monitoring disease progression of AD, PD and DLB.

Alzheimer Disease↗

PubMed2006

Validation of a PCR-based method for the detection of various rendered materials in feedstuffs using a forensic DNA extraction kit.

A method trial was initiated to validate the use of a commercial DNA forensic kit to extract DNA from animal feed as part of a PCR-based method. Four different PCR primer pairs (one bovine pair, one porcine pair, one ovine primer pair, and one multispecies pair) were also evaluated. Each laboratory was required to analyze a total of 120 dairy feed samples either not fortified (control, true negative) or fortified with bovine meat and bone meal, porcine meat and bone meal (PMBM), or lamb meal. Feeds were fortified with the animal meals at a concentration of 0.1% (wt/wt). Ten laboratories participated in this trial, and each laboratory was required to evaluate two different primer pairs, i.e., each PCR primer pair was evaluated by five different laboratories. The method was considered to be validated for a given animal source when three or more laboratories achieved at least 97% accuracy (29 correct of 30 samples for 96.7% accuracy, rounded up to 97%) in detecting the fortified samples for that source. Using this criterion, the method was validated for the bovine primer because three laboratories met the criterion, with an average accuracy of 98.9%. The average false-positive rate was 3.0% in these laboratories. A fourth laboratory was 80% accurate in identifying the samples fortified with bovine meat and bone meal. A fifth laboratory was not able to consistently extract the DNA from the feed samples and did not achieve the criterion for accuracy for either the bovine or multispecies PCR primers. For the porcine primers, the method was validated, with four laboratories meeting the criterion for accuracy with an average accuracy of 99.2%. The fifth laboratory had a 93.3% accuracy outcome for the porcine primer. Collectively, these five laboratories had a 1.3% false-positive rate for the porcine primer. No laboratory was able to meet the criterion for accuracy with the ovine primers, most likely because of problems with the synthesis of the primer pair; none of the positive control DNA samples could be detected with the ovine primers. The multispecies primer pair was validated in three laboratories for use with bovine meat and bone meal and lamb meal but not with PMBM. The three laboratories had an average accuracy of 98.9% for bovine meat and bone meal, 97.8% for lamb meal, and 63.3% for PMBM. When examined on an individual laboratory basis, one of these four laboratories could not identify a single feed sample containing PMBM by using the multispecies primer, whereas the other laboratory identified only one PMBM-fortified sample, suggesting that the limit of detection for PMBM with this primer pair is around 0.1% (wt/wt). The results of this study demonstrated that the DNA forensic kit can be used to extract DNA from animal feed, which can then be used for PCR analysis to detect animal-derived protein present in the feed sample.

Animal Feed↗

PubMed2006

[Proliferation of natural killer T cells in umbilical cord blood and peripheral blood and their different phenotypes].

Purpose of this study was to establish an effective method in vitro to proliferate natural killer T (NKT) cells from umbilical cord blood (UCB) and peripheral blood (PB), and to study their different phenotype. Mononuclear cells (MNC) from UCB and PB were cultured in the presence of IL-2 (100 U/ml), with or without alpha-Galcer. TCR Valpha24 Vbeta11 double positive natural killer T-cells (NKT cells) and their other phenotypes were determined by flow cytometry. The results showed that after expansion for 7 days, TCRValphabeta(+) NKT cells from UCB-MNCs increased by (8.74 +/- 4.37) x 10(2) times as much, but most of them did not express NK1.1 and its TCR Vbeta11(+) was higher than TCR Valpha24(+). After expansion for 14 days, TCR Valphabeta(+) NKT cells from PB-MNCs increased by (3.72 +/- 2.01) x 10(2) times, the expression of NK1.1 was high and its TCR Vbeta11(+) was almost equal to TCR Valpha24(+). It is concluded that human TCR Valpha24 Vbeta11 double positive NKT cells can expand by addition of alpha-Galcer. The proliferation efficiency in UCB-MNCs is greater than that in PB-MNCs. Most of the UCB-NKT is NK1.1(-), while the PB-NKT is NK1.1(+), a new subset of NKT cells.

Cell Proliferation↗

PubMed2006

[Study on mRNA expression of the human novel gene NM23-H1B in ovarian tumor].

OBJECTIVE: To study the expression of the human novel gene NM23-H1B in ovarian cancer. METHODS: Forty-eight samples from patients with ovarian tumor at different clinical stages and 8 from normal ovaries were examined for NM23-H1B mRNA expression by using RT-PCR, northern blot and in situ hybridization. RESULTS: All samples expressed NM23-H1B mRNA through RT-PCR, while the level of expression in ovarian tumor was higher than that of normal ovary. The level of expression in early stage (stage I and II) cancer was higher than in advanced (stage III and IV) cancer. The results of northern blot showed that NM23-H1B was over expressed in ovarian cancer while low expressed in normal ovary or low malignant potential (LMP) ovarian cancer. In early stage carcinoma, the expression level was related with the differentiation of tumor cell. Well-differentiated cancer expressed NM23-H1B mRNA at comparatively higher level. The result of in situ hybridization showed that positive expression rate of NM23-H1B mRNA in ovarian cancer (100%, 40/40) was significantly higher than that in normal ovary (0/8) or LMP ovarian cancer (2/8). CONCLUSION: The novel gene NM23-H1B is related to ovarian cancer.

Adolescent↗

PubMed2006

[Transcriptional inhibitory effect of hepatitis B virus X protein on the expression of p53 tumor suppression gene].

BACKGROUND: To investigate the transcriptional inhibitory role of hepatitis B virus X protein on the expression of p53 tumor suppression gene. METHODS: The promoter sequence of the p53 tumor suppression gene was identified and amplified by bioinformatics and polymerase chain reaction (PCR). The recombinant reporter gene expression vector pCAT3-p53p was constructed and transfected into the hepatoblastoma cell line HepG2 and cotransfected with pcDNA3.1 (-)-X by Fugene 6 transfection reagents. The chloramphenicol acetyl transferase (CAT) activity was detected by enzyme-linked immunosorbent assay (ELISA). The expression of p53 mRNA was further detected by RT-PCR with or without HBV X protein. RESULTS: The reporter vector pCAT3-p53p has been successfully constructed and identified and the p53 promoter could cis-activate the transcription of the CAT gene. The relative expression level of CAT gene in HepG2 cells cotransfected with pCAT3-p53p and pcDNA3.1 (-)-X was lower than the control, and the inhibitory rate was approximately 78%, which indicate that HBV X protein could transcriptionally inhibit the activity of p53 promoter. After transfected with pcDNA3.1 (-)-X, the expression of p53 mRNA was lower than the control. CONCLUSION: HBV X protein could transcriptionally inhibit the expression of p53 tumor suppression gene, which might be a possible molecular mechanism responsible for the development of HBV-associated hepatocellular carcinoma.

Base Sequence↗

PubMed2006

[Effect of three different curcumin pigmens on the prdiferation of vascular smooth muscle cells by ox-LDL and the expression of LDL-R].

OBJECTIVE: To investigate the anti-proliferation of three different structural curcumin pigmen monomers on the bovine VSMC stimulated by ox-LDL and the effect on the expression of LDL-R. METHOD: MTT and FCM were used to observe the anti-proliferation of three different on the bovine VSMC stimulated by ox-LDL and the effect on the expression of LDL-R. RESULT: ox-LDL(2.5,5, 10 mg x L(-1)) had obvious proliferative effect on VSMC, P < 0.05, curcumin (16.5,33,66 micromol x L(-1)), demethoxycurcumin (33,66 micromol x L(-1)) and bisdemethoxycurcumin (66 micromol x L(-1)) had obvious inhibition effect on the proliferation of VSMC stimulated by 10 mg x L(-1) ox-LDL (P < 0.05, curcumin > demethoxycurcumin > bisdemethoxycurcumin) . Three curcumin (16.5,33,66 micromol x L(-1)) could obviously activate the expression of LDLR of VSMC. CONCLUSION: The three different structural curcumin pigmen monomers can not only inhibit the proliferation of bovine VSMC obviously stimulated by ox-LDL, but also promote the expression of LDL-R on bovine VSMC, that may be the mechanism of delaying the development of arteriosclerosis.

Animals↗

PubMed2006

[Characteristics and Influencing factors of Sperm Interaction with Exogenous DNA].

Exogenous DNA localization and the frequency of spermatozoa carrying exogenous DNA after sperm/DNA co-culture are key to a successful sperm mediated-gene transfer (SMGT). In the study, the characteristics and influencing factors of exogenous DNA uptake by spermatozoa were tested using digoxigenin (DIG) labeled DNA as trace. Results showed that goat spermatozoa could spontaneously take up exogenous DNA. The exogenous DNA was initially bound to the outer sperm membrane at postacrosomal region; subsequently party of the bound DNA was internalized into nucleus. There were considerable differences in the capability of spermatozoa from different donors to bind and internalize exogenous DNA. In 35 samples, binding rates (before DNase I digestion) and internalization rates (the positive rate after DNase I digestion) varied between 4.6%-62.4% and 2.1%-53.8%, respectively. For the spermatozoa from the same goat, the binding and internalization capacities were mostly inhibited by the seminal fluid. Compared to ejaculate sperm, the binding rate and internalization rate were increased three and five times in washed sperm cells, respectively. At the same time, capacitated spermatozoa also had lower exogenous DNA uptake (P<0.01). Dead spermatozoa did not complete the internalization process. The highest positive rate (before DNase I digestion) was found in membrane-broken spermatozoa as a result of freeze-thawing and this was independent of the sperm donors. These results suggest that selection of appropriate sperm donors and optimization of sperm processing procedures are the key steps for successful SMGT.

Animals↗

PubMed2006

[The application of several types of large-scale exactitude equipments in the identification of jadeite].

Infrared spectrometer, Raman spectrometer, EPMA, and X-ray powder diffractometer are very effective equipments for the identification of jadeite. Some kinds of raw jadeite fakes occurred in the identification and jewelry market recently. With the methods of infrared spectrometer, Raman spectrophotometer, EPMA, and X-ray powder diffractometer etc., these typical fakes have been systematically studied. These fakes have superficial resemblances such as texture, outer characters and color of minerals in rocks. The relevant information of these fakes has been obtained. Meanwhile, several kinds of rough materials with fake weathering crust and cutting groove were analyzed. These identification methods were compared with each other. Type-B can be tested by infrared spectrometer, Raman spectrophotometer, and X-ray powder diffractometer. The present paper means a lot for the identification, evaluation and business of jadeite.

English Abstract↗

PubMed2006

[Expression of Fas antigen and Fas ligand in acute liver injury induced by carbon tetrachloride in rat].

OBJECTIVE: To investigate the dynamics of expression of Fas antigen and Fas ligand (FasL) in a rat model of carbon tetrachloride-induced acute liver injury, and explore the role of apoptosis in liver injury. METHODS: Thirty-five healthy male Wistar rats were randomly divided into normal control group and experiment group, and the latter group was divided into six subgroups: 3, 9, 16, 24, 36 and 48 hours groups with 5 rats in each group. The liver injury was induced by carbon tetrachloride. Sections of liver tissue were stained with hematoxylin and eosin and observed under optical microscope. Fas antigen and FasL in rat liver were determined at different time points with immunohistochemical method. Hepatocytes apoptosis were observed with terminal deoxynucleotidyl-transferase mediated dUTP-biotin nick end labeling (TUNEL) method. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) concentration in the liver tissues were analyzed at the same time point. Serum aspartate aminotransferase (ALT) and alanine aminotransferase (AST) levels were also determined. RESULTS: Fas antigen and FasL were expressed in the liver tissues of control rats. Following carbon tetrachloride challenge, severe liver injury took place in rats as revealed under microscope and a large amount of hepatocytes apoptosis was found. Hepatic Fas and FasL expression were both increased markedly from 3 to 48 hours after carbon tetrachloride challenge in experiment group. Liver MDA concentration and serum ALT and AST were elevated significantly, while SOD activity decreased remarkably in the experiment group compared with control group (P<0.05 or P<0.01). CONCLUSION: Expression of Fas/FasL is remarkably induced in acute liver injury and accords with the changes of hepatocytes apoptosis, which suggests that apoptosis mediated by Fas/FasL may play an important role in the pathogenesis of acute liver injury.

Animals↗

PubMed2006

[Potential effects of elevated carbon dioxide on forest leaf-feeding insects].

Elevated atmospheric CO2 concentration may result in a decline of leaf nutritional quality (especially N) and an increase in some kinds of defensive secondary components such as phenolic compounds. The changes in tree phytochemistry, combined with the effects of elevated CO2 per se, have a potential impact on leaf-feeding insects. This paper reviewed the effects of elevated CO2 on the performance of leaf-feeding forest insects at individual level and community level. The elevated CO2 per se had very little influence on the metabolism of insect. Over half of the tree-insect experimental system showed that under high CO2, the performance of individual insect became poorer, while the others showed that insect had little or no response to the treatments. The direction and magnitude of the changes in insect performance could be affected by various factors, and the effects of treatments were strongly species-dependant. The magnitude of the changes in phytochemistry, the sensitivity and adaptive capacity of insect to poorer leaf quality, the differences in plant growth conditions and experimental methods, and the mediated effects of other environment factors, e. g., soil NO3-, light, temperature, and O3, were all closely related to the final performance of insect. But, the larvae's consumption usually increased under enriched CO2 treatment, which was widely thought to be a compensatory response for poorer plant quality. The experiments on forest community level found identically a reduction in herbivory, which was contrary to the results from small-scale experiments. The change of insect population and the true response of consumption by leaf-feeding forest insects under CO2 enrichment environment remain unclear, and more field-based experiments need to be conducted.

Animals↗

PubMed2006

[The role of subtypes of voltage-gated K+ channels in pulmonary vasoconstriction induced by 15-hydroeicosatetraenoic acid].

AIM: To observe the effect of subtypes of Kv channels in rat pulmonary artery smooth muscle cells (PASMCs) on the process of pulmonary vasoconstriction induced by 15-HETE. METHODS: In the present study, ring of rabbit PA with specific Kv channel blockers were employed to functionally identify certain channel subtypes that took part in the process of 15-HETE induced pulmonary vasoconstriction; RT-PCR and Western blotting analysis were also used to measure the expression of subtypes of Kv in PASMCs exposed to 15-HETE,chronic hypoxia. RESULTS: Blocking of Kv1. 1, Kv1. 2, Kv1. 3 and Kv1. 6 channels did not affect 15-HETE induced vasoconstriction in normoxic rats; 15-HETE did not affect expression of Kv1. 1 and Kv1. 2 channels; 15-HETE significantly downregulated the expression of mRNA and protein of Kv1. 5 and Kv2. 1 in rat PASMCs. CONCLUSION: The results suggested that hypoxia may block Kv1. 5 and Kv2. 1 channels via 15-HETE mediated mechanism, leading to decrease numbers of functional Kv1. 5 and Kv2. 1 channels in PASMCs, leading to PA vasoconstriction.

Animals↗

PubMed2006

[Developing of a new multicolor-fluorescent labeled STR amplification kit].

OBJECTIVE: To develop a PCR-based STR system for genotyping of 18 loci (Amelogenin, D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D16S539, TH01, TPOX, CSF1PO, D7S820, D2S1338, D19S433, D12S391 and D19S253). METHODS: By using primers labeled with four color fluorescent (FAM, HEX, TAMRA and ROX), two multiplex amplification reaction systems were developed to genotype Amelogenin and 17 STR loci. RESULTS: Amelogenin and these 17 STR loci were genotyped successfully in different kinds of biological samples by the kit. CONCLUSION: The STR amplification kit developed in our study gives a new approach to genotype these 18 loci in a efficient, steady and reliable way.

Alleles↗

PubMed2006

[Study on a fatal pregnant woman died from by avian influenza (H5N1)].

OBJECTIVE: To ascertain the causation of a pregnant woman with undefined pneumonia reported from the People's Hospital of Tongling city in Anhui province on November 2005. METHODS: Epidemiological and clinical information of the case was collected from the keypersons close to the case and referring to the medical record. A medical observation was carried out on the close contacts of the case and sick or dead poultry. Tracheal aspirates being collected were tested by both RT-PCR and real-time PCR to detect viral nucleic acids of A/H5N1, and were inoculated into special pathogen free (SPF) embryonated hens' eggs. RESULTS: The pregnant woman was found to have been contacted with the sick/dead poultry directly on the 4th day before onset of illness. All the 122 close contacts were healthy after a 10-day medical observation. The major clinical features of the case were viral pneumonia with rapidly developed leukopenia and lymphopenia. The progress to acute respiratory distress syndrome and multiple organ dysfunction syndromes was found at clinical presentation. HA and NA gene of A/H5N1 virus were positive. The 8 gene fragments of A/Anhui/1/2005 (H5N1) isolated from the tracheal aspirates had not carried genes from a human virus through reassortment, and the receptor-binding site of the hemagglutinin was polybasic cleavage site. CONCLUSION: This was the first documented case of H5N1 infection in pregnant woman. The immunotolerant state of pregnancy might have predisposed to the fatal outcome of the patient.

Adult↗

PubMed2006

[One-stage repair of unilateral cleft lip and nasal deformity].

OBJECTIVE: To investigate the method for simultaneous correction of nasal deformity and unilateral cleft lip so as to decrease the secondary operation for the deformity. METHODS: The Millard procedure (or Millard plus triangle flap insertion) was used to repair the unilateral cleft lip. Through the incisions, the greater alar and nasalis were repositioned to the normal anatomical positions. The deviated septum and columella were corrected by cutting the abnormal attachment of the orbicular muscle of mouth to the anterior nasal spine. The mattress sutures through the tip of the columella and ala nasi helped to recover the shape of the nostril. RESULTS: 108 patients were treated with this method. They aged from one month to 19 years, included 30 with second degree cleft lip and 78 with third degree cleft lip. The follow-up for as long as 3 years showed satisfactory results. CONCLUSIONS: This technique can eliminate the severe cleft nasal deformity and elevate the displaced alar cartilage at the time of lip repair without interference with nasal growth. It is recommended for the treatment of unilateral cleft lip with severe nasal deformity.

Abnormalities, Multiple↗

PubMed2006

Stimulation of nisin production from whey by a mixed culture of Lactococcus lactis and Saccharomyces cerevisiae.

The production of nisin, a natural food preservative, by Lactococcus lactis subsp. lactis (ATCC 11454) is associated with the simultaneous formation of lactic acid during fermentation in a whey-based medium. As a result of the low concentration and high separation cost of lactic acid, recovering lactic acid as a product may not be economical, but its removal from the fermentation broth is important because the accumulation of lactic acid inhibits nisin biosynthesis. In this study, lactic acid removal was accomplished by biological means. A mixed culture of L. lactis and Saccharomyces cerevisiae was established in order to stimulate the production of nisin via the in situ consumption of lactic acid by the yeast strain, which is capable of utilizing lactic acid as carbon source. The S. cerevisiae in the mixed culture did not compete with the nisin-producing bacteria because the yeast does not utilize lactose, the major carbohydrate in whey for bacterial growth and nisin production. The results showed that lactic acid produced by the bacteria was almost totally utilized by the yeast and the pH of the mixed culture could be maintained at around 6.0. Nisin production by the mixed culture system reached 150.3 mg/L, which was 0.85 times higher than that by a pure culture of L. lactis.

Animals↗

PubMed2006

Optimization of L-(+)-lactic acid production using pelletized filamentous Rhizopus oryzae NRRL 395.

Lactic acid is used as a food additive for flavor and preservation and a precursor in the development of poly-lactic acid, a product used to make biodegradable plastics and textiles. Rhizopus oryzae NRRL 395 is known to be a strain that produces optically pure L-(+)-lactic acid. The morphology of Rhizopus cultures is complex, forming filamentous, clumps, and pellet mycelia. Different morphology growth has significant effects on lactic acid production. In bioreactors, the filamentous or clump mycelia increase the viscosity of the medium, wrap around impellers, and block the nutrient transportation, leading to a decrease in production efficiency and bioreactor performance. Growing fungi in pellet form can significantly improve these problems. In this study, factors that affect lactic acid production in pelletized flask cultures using R. oryzae NRRL 395 were investigated in detail. Completely randomized designs were used to determine the influence of culture temperature, time, concentration of glucose, and inoculum size. Lactic acid fermentation using clump and pellet morphologies were performed in a 5 L fermentor at the optimal values obtained from flask culture. Finally, fed-batch culture was used to enhance the lactate concentration in broth. The final lactate concentration of fed-batch culture reached 92 g/L. The data presented in the article can provide useful information on optimizing lactic acid production using alternative source materials.

Biofilms↗

PubMed2006

[Studies of the factors linked to the bacteriostatic ability of Lactobacillus in human vagina].

OBJECTIVE: To study the factors linked to the bacteriostatic ability of Lactobacillus in human vagina, and the relationship between the Lactobacillus and the Candida albicans. METHODS: The content of H2O2, in the upper culture mediums of Lactobacilli were detected at different incubation time. Selecting the strains with vary bacteriostatic ability by Oxford cup test, detecting pH of these strains cultured after different time. After co-cultivation of the Lactobacillus, which has the strongest bacteriostatic ability, Candida albicans and Staphylococci for different incubation time, quantities of these mixed cultures were investigated. RESULTS: The date of pH and the size of the bacteriostatic ring are negative correlation. There is not obvious relationship between the ability of producing H2O2 and the bacteriostatic ability of Lactobacillus. The study of the relationship between bacteria shows that the quantity of Staphylococci is as this: Staphylococci alone > Staphylococci + Lactobacillus > Staphylococci + Lactobacillus + Candida albicans. CONCLUSION: The bacteriostatic ability of Lactobacillus is positivly related to its acid producing ability, and is not obvious to H2O2 content. After 36 hours cultivation time, Candida albicans can boost up the bacteriostatic ability of Lactobacillus.

Adult↗

PubMed2006

[Research on polyhydroxyalkanoate form a key aspect to enhanced biological phosphorus transformation].

To investigate the influence of PHB and PHV formed on phosphorus (P) release, uptake and removal during enhanced biological phosphorus removal (EBPR), anaerobic/aerobic batch experiments were conducted with biomass acclimated with propionic to acetic acid carbon molar ratios of 0.5 and 2 on two sequencing batch reactors (SBR1 and SBR2). Statistically significant correlations between polyhydroxyalkanoate (PHA) quantity and form and P release/uptake and removal were observed (R2 >0.90). The regression coefficients showed that for biomass cultured with customizing wastewater P release and uptake were both a function of PHB but not of PHV, but higher P removal was largely because of PHV as the predominant type rather than PHV. For biomass cultured with different ratios of propionic to acetic acid, the SBR2 biomass synthesized and utilized more PHB and less PHV and showed higher net P removal (average increase of 16.69%) than SBR1. Thus acetate/propionate content of influent had a major influenceon PHA type and quantity and determine phosphorus (P) release, uptake and removal. Accordingly, PHB and PHV transformations should be taken into account as key aspect for optimizing EBPR.

Bacteria, Aerobic↗