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Biomedical subjects

Yan Liu

Publications and source records attributed to Yan Liu.

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

[Relationship between M3 receptor and myocyte apoptosis induced by acute myocardial infarction].

AIM: To explore the effects of M3 receptor on myocyte apoptosis induced by acute myocardial infarction in rats. METHODS: Rat model was induced by ligation of the anterior branch of the left coronary artery. All animals were divided into four groups: sham-operated group, occlusion group, choline group (10 mg x kg(-1), iv), and 4DAMP (4-diphenylacetoxy-N-methylpiperidine-methiodide) group (0.12 mg x kg(-1), iv). The serum malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were determined. The infarct size areas on the myocardium were identified by TTC staining. The apoptosis in cardiomyocyte was detected by TUNEL assay and apoptosis-related proteins in Bcl-2 and Fas expression were measured by immunohistochemistry assay. RESULTS: M3 receptor agonist choline reduced serum MDA content and increased SOD activity. The myocardial expression of Bcl-2 was increased, whereas the expression of Fas was decreased by choline. However, blockade of M3 receptor by 4DAMP completely inhibited these effects of choline on cardiac myocytes. CONCLUSION: Activation of M3 receptor has protective effect on myocyte apoptosis induced by acute myocardial infarction in rat, and this effect might be related to modulating the expression of some immediateearly genes including Bcl-2 and Fas.

Animals↗
PubMed2004

[Construction and expression of DNA-binding domain plasmid with hepatitis B virus e antigen in yeast double hybrid system].

BACKGROUND: Using hepatitis B virus e antigen (HBeAg) gene to construct the DNA-binding domain vector, which can express HBeAg in yeast cell, and can be used in yeast double hybrid as "bait plasmid" to look for the gene from the cDNA library, which expresses the protein that can interact with HBeAg. METHODS: PCR was performed to amplify the HBeAg gene from a sera of hepatitis B patient. The product of the amplification was inserted into T-vector and was verified by sequencing. Then it was inserted into the "bait" plasmid pGBKT7 after the digestion with the restricted endonuclease of EcoR I and Sal I. The plasmid was transformed into the yeast cell. PCR was used to verify whether the plasmid was transformed into yeast. The HBeAg protein expressed in the cell was confirmed by Western blot. Using nutrition selection assay to verify the constructed plasmid alone could not activate the reporter gene in the yeast cell. RESULTS: Sequenced and digested by two endonucleases, the recombined vectors pGBKT7-eAg produced anticipated fragment. PCR verified that there was HBeAg fragment in the yeast. Having assayed by Western blotting, it was shown that the yeast cell transformed with pGBKT7-eAg vector had positive signal which could not be seen in the control. Tested by the nutrition selection assay, the recombined vectors pGBKT7-eAg could not activate LacZ reporter gene in the yeast. CONCLUSION: DNA-binding domain plasmid was successfully constructed and could express HBeAg proteins in the yeast cell but could not activate transcription of LacZ reporter gene alone. The recombined plasmid can be used in yeast double hybrid.

Genetic Vectors↗
PubMed2004

Effect of adenovirus-mediated p27 gene expression on the proliferation and apoptosis of HL-60 and Raji cell lines.

BACKGROUND: p27 is an essential mediator of cell cycle control, which plays a key negative role in the proliferation and tumorigenesis of certain cell types. Here, we designed this study to explore the possible effects of p27 on the proliferation and apoptosis of HL-60 and Raji cell lines. METHODS: HL-60 and Raji cells were transfected with p27 via an adenovirus-mediated approach. The efficiency of Adp27 infection and the expression of p27 mRNA and protein were evaluated by X-gal staining, RT-PCR, and flow cytometry. The proliferation and apoptosis of HL-60 and Raji cells were estimated by means of trypan blue staining, MTT assay, Annexin V/PI, and DNA ladder electrophoresis. RESULTS: The infection efficiencies in HL-60 and Raji cells were 40.3% and 32.0%, respectively. RT-PCR and flow cytometry showed that there was significant expression of p27 mRNA and protein in HL-60 and Raji cells infected with Adp27; on the other hand, uninfected HL-60 cells showed faint traces of p27 mRNA and protein and Raji cells showed nearly no signs of p27 mRNA and protein. As demonstrated by a cell growth curve and by an MTT assay, strong time-dependent proliferation inhibition was apparent in HL-60 and Raji cells infected by Adp27. After 72 hours of infection, the Annexin V+/PI- apoptotic cell rates in HL-60 and Raji cell lines were 46.9% and 35.7%, respectively, significantly higher than in the control groups (4.7% and 5.6%, respectively). Typical DNA ladder bands were detectable in HL-60 and Raji cells after 48 hours of Adp27 infection. CONCLUSIONS: Adenoviral vector-mediated p27 gene transfection of HL-60 and Raji cells leads to the inhibition of cellular proliferation and the promotion of cell apoptosis. This technique may provide an approach to gene therapy for leukemia or lymphoma.

Adenoviridae↗
PubMed2004

[Stability of molar relationship after orthodontic treatment in Class II division 1 malocclusions treated by extraction].

OBJECTIVE: To investigate the changes of occlusal relationship in posterior teeth among the pre-treatment, post-treatment, and to analyze some possible factors which may relate to the relapse of posterior occlusal relationship. METHODS: 29 finishing Class II division 1 cases treated by extraction with full records selected were included. The sample consists of 12 males, 17 females. The follow-up lateral head films and study casts were taken at least 2 years after orthodontic treatment. The cephalograms were measured by computerized program and the study casts measured by caliper. RESULTS: Improvements of molar relationship were shown during treatment and a little bit changes during follow-up. During the treatment, the amount of mesial movement of the lower molars was more than the upper molars in dental Class II malocclusion and the amount was similar between upper and lower molars in skeletal Class II malocclusion although the ANB angle decreased significantly. During the follow-up stage, the movement tendency between upper and lower molars was reversed. The sagittal growth pattern of mandible and irregularity of upper incisors were nearly correlated with the relapse of molar relationship. CONCLUSION: The stability of molar relationship is acceptable during the follow-up stage in Class II malocclusion. The improvement of molar relationship depends on the difference of mesial movements between upper and lower molars in dental Class II malocclusion. However, in skeletal Class II malocclusion the improvement of jaw relationship does the effect. The positive growth of mandible and crowding of upper incisors may affect the relapse of molar relationship.

Cephalometry↗
PubMed2004

[Mutual interaction between hepatitis B virus antigen and metallothionein].

OBJECTIVE: To screen and identify the protein interacting with HBV antigen in hepatocytes. Then investigate the biological functions of hepatitis B virus antigen in the pathogenesis of hepatitis B and seek effective methods to prevent and treat it. METHODS: The yeast two-hybrid system-3 technique was used to construct HBV PreS2, HBeAg, HBcAg, HBxAg bait plasmids. The bait plasmids transformed the yeast AH109 and expressed themselves in it. After being identified by SDS-PAGE and Western blot, the AH109 yeast was mated with yeast Y187 containing liver cDNA library plasmid in 2 x YPDA medium to form diploid yeast and was then plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) and synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing x-alpha-gal for screening. Plasmids of blue colonies were extracted and transformed into Escherichia coli, then analyzed by DNA sequencing and bioinformatics. To further prove the interaction between HBV antigen and metallothionein, translation was performed by using reticulocyte lysate and coimmunoprecipitation was displayed in vitro. RESULTS: Genes coding for HBV antigen binding protein were successfully cloned and metallothionein was found in that protein. The interaction between HBeAg, HBcAg and HBxAg and metallothionein were further proved by coimmunoprecipitation in vitro. CONCLUSION: The interaction between HBV antigen and metallothionein indicates that metallothionein may participate in the pathogenesis of hepatitis B

Hepatitis B↗
PubMed2004

[Study on binding of HBeAg to CD81].

AIM: To investigate the interaction between HBeAg and CD81. METHODS: The CD81 gene was amplified by RT-PCR from HepG2 cells. The recombinant expression vector pGADT7-CD81 was constructed by routine molecular biological method. The auxotroph yeast cells were cotransfected with pGADT7-CD81 and pGBKT7-eAg and plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing x-alpha-gal. The binding of HBeAg to CD81 was also detected in vitro translation and coimmunoprecipitation test. RESULTS: The recombinant expression vector was constructed and confirmed by restriction enzyme (EcoR I and BamH I) digestion and DNA sequencing analysis. The positive yeast clones could grow and from blue colonies on SD/-Trp-Leu-His-Ade/x-alpha-gal medium. The result of immunocoprecipitation showed that HBeAg could bind to CD81. CONCLUSION: HBeAg can bind to CD81, suggesting that CD81 plays an important role in the pathogenesis of HBV.

Antigens, CD↗
PubMed2004

[Changes of profile prominence in borderline cases with extraction and non-extraction orthodontic treatment].

OBJECTIVE: To compare the treatment effect on the prominence of profile in borderline cases between extraction and non-extraction treatment. METHODS: The sample consisting of 33 borderline cases based on the judgment of 5 orthodontic specialists was divided into three groups according to the treatment way selected by the doctor in charge of the case. Three groups comprised 12 non-extraction cases, 13 four first premolars extraction cases and 8 four second premolars extraction cases. Structure superimposition was used to measure landmarks displacements which reflect the change of profile prominence before and after orthodontic treatment using pretreatment FH plane as a frame of reference. RESULTS: Only the prominence of upper and lower incisors showed statistically significance between the extraction and non-extraction treatments. There was no statistically significant difference between the extraction of four first premolars and second premolars. CONCLUSION: The main effect of extraction vs. non-extraction on profile of borderline cases is the prominence of upper and lower incisors, while their influences on upper and lower base bone and soft-tissue profile are not obvious.

Cephalometry↗
PubMed2004

[The absorption kinetics of silymarin microemulsion in rat intestine].

AIM: To survey the morphology and size distribution of silymarin microemulsion, to investigate the absorption of silymarin microemulsion in rat intestine compared with the absorption of silymarin micelle in rat Jejunum. METHODS: The intestine in rats was canulated for in situ recirculation. RESULTS: The absorption rate constants (Ka) of silymarin microemulsion at the entire intestine, ileum jejunum, duodenum and colon were 6.22 x 10(-2), 2.27 x 10(-2), 1.9 x 10(-2), 1.9 x 10(-2), 1.05 x 10(-2) and 0.43 x 10(-2) h(-1), respectively. The absorption rate constants of two kinds of silymarin micelle at jejunum were 0.36 x 10(-2), 0.65 x 10(-2) h(-1). CONCLUSION: Silymarin microemulsion was well absorbed at the middle and lower segments of intestine in rats. The absorption was a first-order process with the passive diffusion mechanism.

Animals↗
PubMed2004

[Amplification and sequencing of the gene coding for mucin-like protein from Schistosoma japonicum].

OBJECTIVE: To amplify and sequence the partial gene coding for mucin-like protein from Chinese isolates of Schistosoma japonicum (SjMLP). METHODS: The antigenic determinants of SmMLP were predicted by PCGENE software and specific oligonucleotide primers were designed and synthesized. Total RNA was isolated from adult worms of S. japonicum using Trizol reagent and the coding region gene of SjMLP was amplified by RT-PCR technique. RESULTS: The coding region of SjMLP gene was specifically amplified by RT-PCR and the size of amplified fragment was 756 base pairs. The DNA sequence analysis result indicated that the coding sequence of the MLP was highly homologous between S. mansoni and S. japonicum. CONCLUSION: The amplified fragment is consistent to the predicted one, providing a basis for cloning and further study on DNA immunization.

Amino Acid Sequence↗
PubMed2004

[Cephalometric comparison of soft-tissue morphology between extraction and non-extraction orthodontic treatment in borderline cases].

OBJECTIVE: To compare soft-tissue morphology changes by cephalometric measurements between extraction and non-extraction orthodontic treatment in borderline cases. METHODS: The samples consisted of 33 cases selected as borderline cases by 5 orthodontic specialists. They were divided into 21 extraction cases (including 13 four first premolar extraction cases and 8 four second premolar extraction cases) and 12 non-extraction cases by checking patients' treatment records. Conventional cephalometric analysis was made to compare soft tissue structures before and after orthodontic treatments and the same comparison was made between two different extraction patterns. RESULTS: No statistical difference was found in pretreatment soft-tissue morphology between extraction and non-extraction groups divided from borderline cases. The PosBs/FH of the four first premolars extraction group was smaller than that of non-extraction group, and the Ns-Sn-Pos of the four first premolars extraction group was smaller than that of four second premolar extraction group. None of the post-treatment soft-tissue measures showed significant statistical differences between four first premolars extraction group and non-extraction group, but there were 6 items showed significant statistical differences between four second premolars extraction group and non-extraction group. Compared with extraction and non-extraction treatments, the most significant soft-tissue changes were: PosBs/FH, LL-SnPos, and Bs-EP . CONCLUSION: Although pre-treatment soft-tissue morphology of second premolar extraction group was close to that of non-extraction group, the post-treatment soft-tissue morphology of first premolar extraction group became closer to that of non-extraction group. Compared with non-extraction treatment, the more significant changes caused by extraction treatment were located in the lower lip and chin, but not the upper lips.

Cephalometry↗
PubMed2004

[Study on 4 human population genetic characters of Mongol and Han in Western inner Mongolia].

From 1998 to 2001, a sample of 2760 Mongol and Han individuals was investigated in 3 areas (Eerduosi city, Xilinguole and Bayannaoer leagues) from Inner Mongolia. Each individual was studied on 4 genetic characters (thumb type, palmar digital formular, fingernail type and plantar digital formular). The result is as follows: (1) The frequencies of the straight thumb were over 60%, and there were no significant sexual differences in all of 6 groups. (2) The frequencies of the ring-finger-longer were much higher in 6 groups, and there were significant sexual differences in 4 groups. (3) The frequencies of the long-shaped fingernail were the highest in all groups, the squat-shaped were the lowest. (4) The big toes were longer than the second toes in most people of 6 groups,but without significant sexual differences in each groups. (5) There were no significant correlations between 4 characters.

Adolescent↗
PubMed2004

[Clinical features of 23 cases of AIDS complicated by tuberculosis].

OBJECTIVE: To discuss the clinical features, treatment and prognosis of patients with AIDS complicated by tuberculosis(TB). METHODS: The clinical features of 23 patients with AIDS complicated by tuberculosis admitted from 1997 to July 2004 were retrospectively analyzed. RESULTS: Of the 23 patients, most (94.3%) were young or middle-aged, and 11 (47.8%) died within half a year. The main HIV transmission was via sexual contact in 15 (65.2%) patients. Loss of body weight by 5 - 15 kg was present in all patients, cough for over 1 month in 15 (65.2%), and multiple opportunistic infections were complicated in most cases. Out of the 23 cases, 14 (60.9%) showed only pulmonary TB, and 8 (34.8%) showed lymph node TB. In 12 cases with infiltrated pulmonary TB, X-ray showed bilateral infiltration and no cavity formation was found. Slightly positive PPD test was found in 2 (8.7%) cases, and positive acid-fast bacilli was detected in sputum in 1 case (4.4%). The pre-treatment CD(4)(+) cell number in 23 patients was much lower than that in AIDS patients without complicated TB (P < 0.05). The pre-treatment CD(4)(+) cell number in patients died shortly after diagnosis was much lower than that in survived patients (P < 0.05). The HIV RNA level in the 23 patients was much higher than that in patients without complication of TB (P < 0.05). The mortality in patients treated with therapy against both TB and HIV was much lower than that in patients untreated or treated only with anti-TB therapy (P < 0.05). CONCLUSIONS: For patients with AIDS complicated by TB, the high negative rate in PPD test and the atypical chest X-ray manifestations are common. However, lymph node TB is quite common with high mortality. The pre-treatment CD(4)(+) level decreases significantly, and is associated with mortality. The TB bacilli may accelerate HIV virus duplication. It is suggested that the patients be treated with a combination of anti-TB and anti-HIV therapies.

Acquired Immunodeficiency Syndrome↗
PubMed2004

The distribution of six biallelic polymorphisms on non-recombining segments of the Y-chromosome in five Chinese populations.

Ancient demographic events can be inferred from the distribution of biallelic polymorphisms of NRY. In our study, six Y-biallelic markers were screened in 326 Y-chromosomes from five Chinese populations: Manchu, Fujian Han, Kazak, Bouyei and Sichuan Han. The chi2-test was performed using the SAS package. ARLEQUIN and SPSS programs were used for pairwise Fst's and genetic clusters, respectively. The M9 (G) and RPS4Y (T) polymorphisms show greater variance in these five populations and are informative and sensible in Chinese population genetic research, while the other four are less polymorphic. Significant differences in the distribution of the six biallelic markers were found between the three southern groups and the two northern groups involved in the present study. The Kazak population demonstrated marked differences not only from the southern populations, but differed notably from the other northern population, the Manchu. This result clearly suggests that the original division of the investigated groups into north and south would not yield optimal results from which useful generalizations could be made. The results have proven to be extremely useful, their analysis not only brought to light important new facts on the population structures, but supplied also useful guidelines for further additional Chinese population genetic research projects.

Alleles↗
PubMed2004

Human alphaA- and alphaB-crystallins prevent UVA-induced apoptosis through regulation of PKCalpha, RAF/MEK/ERK and AKT signaling pathways.

AlphaA- and alphaB-crystallins are distinct antiapoptotic regulators. Regarding the antiapoptotic mechanisms, we have previously demonstrated that under staurosporine treatment, HalphaA- and HalphaB-crystallins can interact with Bax and Bcl-XS, proapoptotic members of the Bcl-2 family, to sequester their translocation into mitochondria, and thus prevent the staurosporine-induced apoptosis. In the present study, we further compared the anti-apoptotic mechanisms of HalphaA- and HalphaB-crystallin in preventing human lens epithelial cells from UVA-induced apoptosis. UVA-irradiation of human lens epithelial cells turned on the apoptotic death program. Moreover, associated with the activation of the death program, UVA also activated the RAF/MEK/ERK signaling pathway. In contrast, p38 kinase and JNK1/2 signaling pathways were not activated. Inhibition of the RAF/MEK/ERK pathway by a dominant negative mutant RAF1 greatly attenuated UVA-induced apoptosis. Expression of the exogenous human alphaB-crystallin prevented UVA-induced activation of RAF/MEK/ERK pathway and thus substantially abrogated UVA-induced apoptosis. In contrast, expression of the exogenous human alphaA-crystallin did not prevent UVA-induced activation of RAF/MEK/ERK pathway. Instead, it activated AKT kinase pathway to promote survival and thus counteracted the UVA-induced apoptosis. Together, our results for the first time reveal that by regulating multiple signaling pathways the two alpha-crystallins can prevent stress-induced apoptosis through different mechanisms.

Apoptosis↗
PubMed2004

Protective effect of M3 receptor on H2O2 -induced apoptosis of rat myocardial cells in vitro.

AIM: To observe the effect of activation of M3 receptor on H2O2 induced apoptosis in cultured rat myocytes and to investigate its possible mechanisms. METHODS: Isolated neonatal cardiomyocytes were cultured. Morphologic changes were observed by microscopy. The apoptosis in cardiomyocyte was detected by terminal deoxynucleotide transferase directed d-UTP nick and end labeling (TUNEL) assay. The expression of apoptosis-related protein in Bcl-2 and Fas was measured by immunohistochemistry assay. [Ca2+]i in single cardiomyocyte loaded with Fluo 3-AM was measured by confocal microscope. RESULTS: H2O2-mediated myocyte apoptosis was attenuated by M3 receptor agonist choline (10 mmol x L(-1)). Pretreatment of cardiac myocytes with choline also increased Bcl-2, decreased Fas expression, and inhibited the increase in FI value of [Ca2+]i in H2O2-stimulated cardiac myocytes. However, blockade of M3 receptor by 4DAMP (10 nmol x L(-1)) completely inhibited the effects of choline on H2O2-stimulated cardiac myocytes. CONCLUSION: Activation of M3 receptor showed protective effect on H2O2-induced apoptosis in cultured rat myocytes and this effect might be related to modulating the expression of some genes including Bcl-2 and Fas as well as the downregulation of [Ca2+]i.

Animals↗
PubMed2004

[Experimental study of K562 cell apoptosis induced by siRNA].

OBJECTIVES: To construct a siRNA expression vector pBCR6 that produces siRNA against bcr/abl mRNA and detect apoptosis rate of K562 cells after pBCR6 transfection. METHODS: Template sequence for siRNA was designed, synthesized and inserted into an expression vector pSilencer1.0-U6. Restriction analysis and sequencing were performed to verify the pBCR6 vector. Then pBCR6 was transfected into K562 cells by X-tremeGene Q2. pSilencer1.0-U6 was used as the control. At different time point after transfection, apoptosis rate was determined by Tunel and Annexin V+ PI with FCM. RESULT: pBCR6 was verified by restriction analysis and sequencing. The apoptosis rate of K562 cells markedly increased at 48 and 72 hour after transfected with pBCR6, and increased in a time-dependent manner [the apoptosis rate of transfected K562 cells was (47.80 +/- 1.63)% at 72 hrs, whereas the control group was (6.67 +/- 0.37)%, P < 0.0001] No prominent change in apoptosis rate was found in the control. CONCLUSION: The siRNA expression vector against bcr/abl mRNA was successfully constructed. The pilot study showed that pBCR6 could effectively induce K562 cells apoptosis. siRNA may be a new tool for molecular target therapy for chronic myelogenous leukemia.

Apoptosis↗
PubMed2004

[ABO genotyping by duplex amplification and oligonucleotide arrays assay].

OBJECTIVE: ABO genotyping for forensic identification by oligonucleotide chip. METHODS: Oligonucleotide microarrays which could detect 3 different SNPs in exon 6 and exon 7 for ABO genotyping were used. Population studies on ABO was carried out in a sample of 115 unrelated Chinese Han individuals. The method was also applied to cases. RESULTS: The technique could identify 6 genotypes of ABO system. According to the results of population studies, no significant deviations from Hardy-Weinberg equilibrium could be found. The observed and expected heterozygosities were 0.591 and 0.616 respectively. The polymorphic information content was 0.544. The average exclusion probabilities in buos and trios was 0.188 and 0.344 respectively. The discrimination power is 0.777. CONCLUSION: The data and case application demonstrated that ABO typing by oligonucleotide probe arrays was a useful technique for paternity testing and individual identification.

ABO Blood-Group System↗