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Biomedical subjects

Yang Liu

Publications and source records attributed to Yang Liu.

At least 217 records · Page 12Linked to original sources

Phase transition of nanostructure zirconias doped with rare earth elements.

Nanostructure zirconias doped with rare earth elements were obtained by coprecipitation. The morphology, structure, and phase transition of the as-prepared samples were studied. According to transmission electron microscopy, the particles appear in near spherical shape and have a mean particle sizes of about 150 nm without change with the rare earth elements. From laser Raman and X-ray diffraction results, it is known that the tetragonal phase of zirconia is stabilized by a certain concentration of the rare earth dopants, and the cubic phase is obtained if enough dopants are added. The crystal lattice increases with the increase of dopant concentration. Moreover, the heavy rare earths are better than the light ones in stabilizing effect. According to our study, laser Raman is more sensitive than X-ray diffraction in monitoring the phase transition.

Crystallization↗

Protection of hepatocytes from apoptosis by a novel substance from actinomycetes culture medium.

A novel substance, #675, found from an Streptomyces sp. SM675 culture medium, dose-dependently stimulates the proliferation of human functional liver cell 4 (FLC4). When FLC4 cells were incubated under conditions without fetal bovine serum (FBS), typical features of apoptotic cell death such as shrinkage and nuclear condensation appeared; high molecular weight (HMW) DNA fragments were found; and caspase-3 and poly (ADP-ribose) polymerase (PARP) proteins were cleaved. When FLC4 cells were incubated with #675 and without FBS, the cells grew healthy, no HMW DNA fragments were found, and caspase-3 and PARP cleavage weakened, suggesting that #675 protects FLC4 cells from apoptosis induced by FBS-deprivation. The quantitative reverse-transcribed polymerase chain reaction did not show differences in PARP or Bcl-2 mRNA expression in FLC4 cells incubated with or without #675, indicating other genes may be involved in this anti-apoptosis effect. These results show that #675 enhances FLC4 proliferation via an apoptosis-inhibition pathway, implying potential pharmacological and clinical applications.

Apoptosis↗

[Expression of hypoxia-inducible factor-1alpha in middle ear cholesteatoma].

OBJECTIVE: To explore the pathogenetic mechanism of middle ear cholesteatoma, the aim of this study is to detect the expression of Hypoxia-inducible factor-1alpha in middle ear cholesteatoma and normal external ear canal skin. METHOD: We used the technology of immunohistochemistry to examine the expression of Hypoxia-inducible factor-1alpha in thirty-one middle ear cholesteatomas and ten samples of normal external ear canal skin. RESULT: The expression of HIF-1alpha was extremely higher in middle ear cholesteatomas than in normal external ear canal skin (P <0.05). CONCLUSION: We found that the higher expression of Hypoxia-inducible factor-1alpha in middle ear cholesteatomas, so we think that Hypoxia-inducible factor-1alpha play an important role in the pathogenetic process of middle ear cholesteatoma, and hypoxia may be an incentive in the pathogenetic mechanism of middle ear cholesteatoma.

Adolescent↗

[Maintaining mechanism of species diversity of land plant communities].

The maintaining mechanism of species diversity of land plant communities is a key and advancing edge in biodiversity study. Botanists and ecologists have presented many hypotheses and theories with controversies, and no general theory system was available. In this paper, the problem was reviewed mainly on two scales. The first was big spatial scale, aiming at the physical and natural factors that affect the species diversity, including histories and ages of plant communities, gradient changes such as latitude gradient, water gradient, altitude gradient and soil nutrients gradient, area effect, and isolation; and the second was concentrated on a special plant community, and mainly discussed the relationships of biodiversity with biotic factors (primary productivity, relationship between species, and gap dynamics) and abiotic factors (succession, disturbance and spatial heterogeneity, and human activity).

Biodiversity↗

[Effects of nanotopography of bioactive surface on Pseudomonas fluorescence cell adhesion].

The nanoparticle-modified surfaces were built up by alternating deposition of oppositely charged Al2O3 and SiO2 nanoparticles (from 10 nm to 500 nm) solutions. The properties of these nanoparticle-modified surfaces and the controls were investigated by Atomic Force Microscope for topography analysis. Pseudomonas Fluorescence (PF) cell adhesion was evaluated by microscopic determination of the numbers of cells that adhered to the produced slides exposed to PF cell suspensions on static and dynamic condition. The results show that adhesion of PF to both surfaces readily increases with the time of exposition but the adhered numbers of PF on produced surfaces are considerably higher than that on controls in static condition. Cell morphologies on these nanoparticle-modified surfaces studied by inverted microscope show that the adhered PF on the produced surfaces are more in presence of clusters, which contributes more to the total adhering numbers in the late of cell adhesion assays. Meanwhile on controls the cells rarely attained confluence and had a single shape. The significant statistical correlation observed between nanoparticle-modified surfaces and control adds a new concept to the studies of substratum topography influence on cell behavior. The results suggest that nanoparticle-modified surfaces may enhance the interactions between PF cell and slides.

Bacterial Adhesion↗

[The identification of Mycobacterium tuberculosis isolates by DNA typing technique].

OBJECTIVE: To assess the application of IS6110-restriction fragment length polymorphism (RFLP), Spoligotyping and mycobacterial interspersed repetitive unit (MIRU) in epidemiological studies of tuberculosis and to discuss the characteristics of Mycobacterium tuberculosis strains in different regions in China. METHODS: Mycobacterium tuberculosis strains, with a total number of 158 isolates, were subjected to IS6110-RFLP, Spoligotyping and MIRU. RESULTS: The numbers of patterns produced by IS6110-RFLP, Spoligotyping, and MIRU typing were 118, 20 and 105 respectively. The discriminatory power of IS6110-RFLP was higher than that of Spoligotyping. However, when the copies of IS6110 were lower than 10, the discriminatory power of Spoligotyping improved obviously. The discriminatory power of MIRU typing was close to that of IS6110-RFLP for typing of Mycobacterium tuberculosis. In MIRU loci, there were four loci (loci 4, 10, 26, 40) with higher diversity. Significant differences among the Mycobacterium tuberculosis between Guangdong and other regions in clustered rate and the proportion of Beijing genotype (P < 0.05) were found. The clustered rates and the proportion of Beijing genotype in Guangdong were lower than that in other regions. CONCLUSION: The results of this study indicated that either IS6110-RFLP, Spoligotyping or MIRU technique was useful for epidemiological studies on tuberculosis in China and the strains in different regions had different characterishes in China.

China↗

[A clinical study of non-erosive reflux disease].

OBJECTIVE: [corrected] To investigate the differences and similarities between non-erosive reflux disease (NERD) and reflux disease (RE). METHODS: This study covered 30 patients who were grouped by endoscopy into the cases of NERD (n=17) or RE (n=13). The two groups' symptom, mentality, and damage to life quality were compared. Biopsy was performed at 3 cm above LES in oesophagus. The patients were placed under ambulatory 24-h oesophageal pH and Bilitec2000 monitoring. And their responses to the same anti-reflux treatment were evaluated. RESULTS: (1) The proportion of female (58.82%) in NERD group was much higher than that (15.38%) in RE group (P<0.05). (2) There was no remarkable difference in symptom, damage to life quality between the NERD and RE groups (P>0.05). But in respect to mentality, the NERD group had significantly higher anxiety and depression scores than did the RE group (P<0.05). (3) No noticeable difference in the pathological results of biopsy was seen between the NERD and RE groups (P>0.05). (4) The NERD group had less abnormal reflux, compared with the RE group (P<0.05). (5) The NERD group gave less response to treatment, compared to the RE group (P<0.05). CONCLUSION: NERD may be a kind of reflux disease different from RE.

Adult↗

[Study on the interface of Ti-porcelain fused under different surface treatment].

OBJECTIVE: This study was made to observe the topography and ionic diffusion of the elements titanium, silicon, et cetera in the Ti-porcelain interface area which was pretreated with different methods. METHODS: Ti-bond porcelain was fused on commercial pure titanium (CPT) with 8 different pretreatment methods; according to the temperature of the preoxidation, there were 300 degrees C, 400 degrees C, 500 degrees C and 600 degrees C groups, and based on the oxidizing-time in the air, there were 5 min, 15 min, 2 h and 24 h groups. The topography and ionic diffusion of elements in the Ti-porcelain interface area were observed with scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) respectively. RESULTS: There were clefts and exfoliations in the 500 degrees C pre-oxidation group and 600 degrees C pre-oxidation group in SEM images. The distribution of titanium in the interlayer in EPMA images decreased from the titanium surface to porcelain, which was opposite to the distribution of silicon. CONCLUSION: The clefts and exfoliations suggested the position of the fracture and brittleness of alpha-Ti[o] layer. The widths of ionic diffusion in the eight groups were different, but it was difficult to measure and compare them exactly.

Dental Alloys↗

[Expression of p120ctn and its significance in non-small cell lung cancer].

OBJECTIVE: To investigate the expression of p120(ctn) in non-small cell lung cancer (NSCLC) and its correlation with the clinical and pathologic parameters. METHODS: Immunohistochemistry (S-P method) was used to detect the expression of p120(ctn) in 143 NSCLC cases. The variation of protein expression was further analyzed in 36 cases by Western blot. The correlation with clinical and pathologic parameters was studied. RESULTS: Immunohistochemically, normal bronchial cells showed membranous expression for p120(ctn), while NSCLC was characterized by cytoplasmic or diminished membranous staining. The rate of abnormal p120(ctn) expression was 79.7% (114/143). There was a significant correlation between abnormal expression of p120(ctn) and tumor differentiation, clinical stage, lymph node metastasis and poor prognosis (< 0.05), but not histologic typing. Western blot showed that the total amount of p120(ctn) in normal bronchial cells was significantly higher than that in NSCLC. The p120(ctn) isoform 1 (120,000) and isoform 3 (100,000) were expressed in normal lung tissue, while there was a reduced expression or absence of isoform 1 in NSCLC. CONCLUSION: The expression of p120(ctn) is abnormal in NSCLC; p120(ctn) may serve as a useful prognostic marker for NSCLC.

Aged↗

[The surgical treatment of severely injured vagina].

OBJECTIVE: To investigate the surgical methods of treating severely injured vagina. METHODS: A retrospective study was carried out on the clinical materials and results of 7 patients suffered from severe vaginal injury. RESULTS: Different surgical approaches such as trans-suprapubic, transperineal or both approaches were applied according to the position of the atresia, meanwhile, different surgical methods such as skin graft, free flap transplantation, vaginal mucous flap advancement, direct anastomosis of the two ends, "Z" plasty was used to repair the vagina according to the different defect of the vagina, except for 1 case complicated with vaginorectus fistula, all the other cases were achieved satisfactory results. CONCLUSIONS: The accurate judgment of the severity of the vaginal injury and the understanding of the changed anatomy around the injured vagina was the key points to the success of the surgical treatment of traumatic vaginal atresia.

Female↗

[Expression of hypoxia-inducible factor-1alpha in nasal polyps and its correlation with vascular endothelial growth factor and inducible nitric oxide synthase].

OBJECTIVE: To detect the expression and distribution of hypoxia-inducible factor-1alpha (HIF-1alpha) in nasal polyps, to explore the relationship of HIF-1alpha with vascular endothelial growth factor (VEGF) and inducible nitric oxide synthase (iNOS), and to investigate the role of HIF-1alpha in the pathogenetic mechanism of nasal polyps. METHODS: Using the techniques of immunohistochemistry and reverse transcription polymerase chain reaction, the expressions of HIF-1alpha, VEGF, iNOS protein and HIF-1alpha mRNA were examined. The specimens were obtained from patients underwent SMR surgery during the same period, including thirty-one nasal polyps and ten inferior turbinate tissues. RESULTS: According to immunohistochemical research, the expressions of HIF-1alpha, VEGF and iNOS were higher in nasal polyps than those in inferior turbinate tissue (P < 0.01); The result of RT-PCR showed that there was no significant difference between the expression of HIF-1alpha mRNA in nasal polyps and inferior turbinate tissues (P > 0.05); No correlation was found between the expression of HIF-1alpha and the clinical stages of nasal polyps (F = 0.42, P > 0.05); There was a positive correlation between the expression of HIF-1alpha and that of VEGF (r = 0.630, P < 0.05). No significant correlation was found between the expression of HIF-1alpha and that of Inos (r = 0.144, P > 0.05). CONCLUSIONS: Although the mRNA level of HIF-1alpha did not change much, the expression of its protein was significantly higher in nasal polyps than in inferior turbinate tissues. There was no correlation between the expression of HIF-1alpha and the clinical stages. A positive correlation was found between HIF-1alpha and VEGF, but no correlation was detected between the HIF-1alpha and iNOS. In conclusion, our study indicates that hypoxia may play an important role in the pathogenetic mechanism of nasal polyps.

Adolescent↗

[Investigation on prevalence and influencing factors of three chronic diseases in elderly adults].

OBJECTIVE: To find out the prevalence of hyperlipemia, hypertension and diabetes, and explore the primary influence factors. METHODS: The survey consists of questionnaire and health examination on 2120 elderly adults aged above 45 year old. The possible influence factors and the primary factors in 19 factors were analyzed and screened by case-control study and logistic regression analysis. RESULTS: This investigation showed that the prevalence rates of hyperlipemia, hypertension, and diabetes were 50.12%, 44.26% and 8.74% respectively. For hyperlipemia: monthly income, BMI, WHR, coarse food grain were primary factors. For hypertension: age, smoke, intensity, BMI, WHR were primary factors. For diabetes: family history of disease, BMI, WHR, coarse food grain, exercises were primary factors. CONCLUSION: The risk factors of the three chronic diseases were obesity and unhealthy life styles, and the protective factors were coarse food grian and exercises. It's important to decrease prevalence of chronic diseases in community by controlling these risk factors.

Aged↗

[The in vitro model of inhalation anesthesia using rodent ventilator].

OBJECTIVE: To set up a method of applying inhalation anesthesia in rodent using rodent ventilator and to study the dynamic procedure of the in vitro model. METHODS: The output port of the anesthesia machine was connected to the input port of the rodent ventilator, which was connected to a syringe simulating the lung. After supply of anesthetic gas, the gas samples from the input port of the ventilator and the syringe in the end-expiratory phase were collected at 10, 20, 30, 40, 50, 60, 90, 120, 180, 300, 600 and 900 seconds respectively and were determined using the gas chromatography(GC). The ratios of the anesthetic concentrations of the syringe to that of the input port were calculated (CE/CI). In elimination phase, the gas samples from the syringe were collected at 0,10, 20, 30, 40, 50, 60, 90, 120, 180, 300, 600 and 900 seconds respectively and were determined by GC. The ratios of the anesthetic concentrations of the gas at 10, 20, 30, 40, 50, 60, 90, 120, 180, 300, 600 and 900 seconds to that at 0 second were calculated(C'E/C0). RESULTS: CE/CI increased in the inhalation phase, there was an inverse relationship between CE/CI and time, the correlation coefficients were 0.90, 0.95 and 0.93 respectively (P < 0.01). The mathematical fitting equations were y = -0.19 + 0.19x(-1), y = -7.75 + 0.99x(-1), and y = -7.21 + 0.97x(-1) respectively. C'E/C0 decreased in the elimination phase,the correlation coefficients were 0.90, 0.94 and 0.95 respectively (P < 0.01). The mathematic fitting eqations were y = 5.65-0.02x(-1), y = 7.82-0.01x(-1),and y = 8.20-0.01x(-1), respectively. CONCLUSION: The in vitro model of rodent inhalation anesthesia using the rodent ventilator was set up. The establishment of this model has provided a basis for studies on inhalation anesthesia in rodents.

Anesthesia, Inhalation↗

[Survivin antisense oligonucleotide induces human Hep-2 cell apoptosis].

OBJECTIVE: Survivin highly overexpresses in the most of human tumors, and it may play an important role in the development of tumor. The aim of this study was to explore the effects of survivin antisense oligonucleotide (ASODN) on the proliferation and the apoptosis of human Hep-2 cell. METHODS: Hep-2 cells were transfected with survivin ASODN mediated by lipofectamine, MTT [3-(4,5-dimethylthiazol-2-yl)-2, 5 diphenyl tetrazolium bromide] method was used to observe the cell growth inhibitory rate, the expressions of survivin mRNA and protein were detected by reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot respectively. Flow cytometry was used to examine cell apoptosis rate. Kinase activity test was used to detect the changes of caspase-3 activity. RESULTS: Survivin ASODN obviously inhibited the cell growth of Hep-2 cells after transfection. After transfected with survivin ASODN the expressions of survivin mRNA and protein of Hep-2 cells were down-regulated, and apoptosis rate was significantly increased. The activity of caspase-3 increased highly in Hep-2 cells transfected with survivin ASODN, which showed time-dependent. CONCLUSIONS: Survivin ASODN could inhibit the proliferation of Hep-2 cell and induced apoptosis through down-regulating the the expressions of survivin mRNA and protein.

Apoptosis↗

[Changes of cycle and apoptosis of spermatogenic cells and antioxidant capacity in male rats with diabetes mellitus].

OBJECTIVE: To explore the changes of cycle and apoptosis of spermatogenic cells and antioxidant capacity of the serum and testis in male rats with diabetes mellitus. METHODS: Thirty male rats were divided into two groups, 10 for normal control and 20 for the diabetes group. The rats were injected intraperitoneally with streptozocin (TZ) to develop diabetes, and 12 weeks later, their survival rate and testis weight were recorded. The percentage of G0/G, S and G2/M phases and apoptosis in spermatogenic cells were measured with flow cytometry (FCM). Malondialdehyde (MDA) and nitric oxide (NO) levels, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and NO synthase (NOS) activities in the serum and testis were measured with thiobarbituric acid reactive substances (TBARs), nitric acid reoxidized enzyme, xanthine oxidative enzyme, 5,5 Dithiobis (2,2 nitrobenzoate) (TNB) and visible light photometer methods, respectively. RESULTS: Twelve weeks after the male rats got diabetes, their survival rate, body weight and testis weight were significantly lower (p < 0.05), and the percentages of G0/G1 phases and apoptotic spermatogenic cells were obviously higher (P < 0.05) than the normal control. At the same time, the percentage of S and G2/M phases spermatogenic cells decreased. So the spermatogenic cells were arrested in G0/G1 phase. In the diabetic rat serum and testis, especially in the testis, MDA levels were distinctly higher and SOD activities were significantly lower than those in the control. Serum GSH-Px activities of the diabetic rats were significantly lower (p < 0.05), while testis GSH-Px activities were significantly higher than those in control group (P < 0.01). NO contents in the serum and testis of the diabetic rats (P < 0.01) increased significantly, particularly the former, while NOS activities in the serum decreased significantly as compared with the control (P < 0.5). CONCLUSION: The increase in testis and serum MDA levels and NO contents and the decrease in the antioxidant enzyme activity of the diabetic rats may be relevant to spermatogenic disorder caused by the increase of G0/G1 phases arrest and spermatogenic cells apoptosis.

Animals↗

[Expressions of Axin and beta-catenin in non-small cell lung cancer].

OBJECTIVE: To investigate the protein expression of Axin and beta-catenin, the exon 3 mutation status of beta-catenin and their clinicopathological correlations in non-small cell lung cancer (NSCLC). METHODS: A total of 100 NSCLC samples and their corresponding normal lung tissues were obtained from the patients undergoing surgery in the First Affiliated Hospital of China Medical University between 2001 and 2003. Protein expressions of Axin and beta-catenin were detected by immunohistochemistry. DNA sequence alterations of exon 3 of beta-catenin were investigated by polymerase chain reaction (PCR) and direct sequencing. RESULTS: A reduced membranous expression rate of beta-catenin was observed in 80.0% of the cases (80/100) along with a nuclear expression rate of 26.0% (26/100). There was a significant difference in beta-catenin expression between well and poorly differentiated NSCLCs. Well to moderately differentiated NSCLCs showed a reduced expression rate of 70.0% (35/50), in contrast to 90.0% (45/ 50) in poorly differentiated tumors (P = 0.012). Reduced beta-catenin expression rate was 87.3% (48/55) in cases with lymph node metastasis, in contrast to 71.1% (32/45) in cases without lymph node metastasis (P = 0.044). The positive expression rate of Axin was 48.0% (48/100). Well to moderately differentiated NSCLCs demonstrated a 60.0% positive expression rate of Axin (30/50), much higher than poorly differentiated tumors [36.0% (18/50), P = 0.016]. The positive expression rate of Axin in beta-catenin nuclear expressed NSCLCs was 15.4% (4/26), much lower than cases without beta-catenin nuclear expression [59.5% (44/74), P < 0.001]. Axin nuclear expression was found in two cases in this study, suggesting that it may function as a nuclear-cytoplasmic shuttling protein. PCR and direct sequencing failed to reveal any exon 3 mutation of beta-catenin gene. CONCLUSIONS: The reduced membranous expression of beta-catenin is associated with poorly differentiated and lymph node positive NSCLCs. The expression of Axin is inversely correlated with the degree of tumor differentiation and nuclear expression of beta-catenin. The exon 3 mutations do not contribute to the abnormal protein expression of beta-catenin in NSCLCs.

Adult↗

[The prevalence of obstructive sleep apnea-hypopnea syndrome in adults aged over 20 years in Changchun city].

OBJECTIVE: To investigate the prevalence of obstructive sleep apnea-hypopnea syndrome (OSAHS) in adults aged over 20 years in Changchun city, providing epidemiological data for treatment and prevention of the disease. METHODS: 3,960 subjects were derived from a stratified cluster and random sampling of the population in two districts of Changchun city. They were asked to answer the questions from a questionnaire in their houses. According to the degree of snoring, 200 subjects with a snoring score >or= 2 degree were selected to undergo polysomnography for a whole night and the prevalence of the disease was estimated. RESULTS: A total of 3,648 (97.64%) validated questionnaires was collected. Of them 31.00% had a snoring score >or= 2 degree, the prevalence was higher in males (40.07%) than in females (21.76%). The prevalence of snoring was higher in drivers (42.47%) than in other occupations. The estimated prevalence of OSAHS defined by apnea-hypopnea index (AHI) >or= 5, Epworth sleepiness scale (ESS) >or= 9 and arterial oxygen saturation (SaO(2)) < 90% was 4.81%. CONCLUSIONS: The estimated prevalence of OSAHS in adults aged over 20 years in Changchun city was 4.81%. Doctors should pay more attention to the disease and the ordinary people should be informed of the health impact of snoring and OSAHS.

Adult↗

Relationship of homocysteine and gene polymorphisms of its related metabolic enzymes with Alzheimer's disease.

OBJECTIVE: To investigate the relationship of plasma homocysteine (Hcy) levels and the gene polymorphisms of N5, N10-methylenetetrahydrofolate reductase (MTHFR), cystathionine beta-synthase (CBS) with Alzheimer's disease (AD). METHODS: Plasma Hcy levels were measured by means of high voltage capillary electrophoresis with ultra-violet detection, the polymorphisms of C677T in exon 4 of MTHFR gene and 844ins68 in exon 8 of CBS gene were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 105 AD patients and 102 non-AD controls. All controls were excluded from cardiocerebrovascular disorders and other diseases. RESULTS: The plasma Hcy level in AD patients (16.04 +/- 3.84 micromol/L) was significantly higher than that in the controls (11.94 +/- 3.87 micromol/L, P < 0.001). There were no significant differences of the genotype and allele frequencies of MTHFR C677T mutation and CBS 844ins68 mutation between the patients and controls. However, the T allele of MTHFR gene was found to relate with the plasma Hcy level increase in all subjects. CONCLUSION: The elevated plasma Hcy level in AD patients is probably involved in the pathogenesis of AD, which may be due to the environmental factor rather than genetic factors of the mutations of MTHFR and CBS.

Aged↗