Biomedical subjects

Yan Gao

Publications and source records attributed to Yan Gao.

At least 55 records · Page 3Linked to original sources

PubMed2006

[Puerarin suppresses the proliferation of vscular smooth muscule cells and c-fos and bcl-2 protein expression].

OBJECTIVE: To observe the role of puerarin on the proliferation of vascular smooth muscle cells(VSMC) induced by thrombin (T) and the effect of puerarin on the c-fos and bcl-2 protein expression. METHOD: Cell number and cell cycle analysis using flow cytometry were adopted as two different indicators of effects on proliferation of VSMC. Western blot was used to indicate the changes of c-fos and bcl-2 protein after 24 h of treatment of T and puerarin. RESULT: 1.5 x 10(-5) - 1.5 x 10(-3) mol x L(-1) puerarin could significantly suppress this stimulation of VSMC proliferation and DNA synthesis induced by T. Western blot demonstrated that after 24 hour of treatment with T and puerarin, T could significantly increase c-fos and bcl-2 protein and 1.5 x 10(-5) - 1.5 x 10(-3) mol x L(-1) puerain could significantly suppress this increase. CONCLUSION: puerarin can suppress the proliferation and DNA synthesis of VSMC promoted by T. This inhibitory effects of puerarin are closely related with the suppression of c-fos and bcl-2 protein.

Animals↗

PubMed2006

Aberrant expression of beta-catenin, Pin1 and cylin D1 in salivary adenoid cystic carcinoma: relation to tumor proliferation and metastasis.

The aims of this study were to investigate the expression levels of beta-catenin, Pin1 and cyclin D1 in salivary adenoid cystic carcinomas (SACC ) and to evaluate its clinical importance, furthermore, to elucidate whether beta-catenin expression was aberrant in SACC and whether Pin1 was involved in aberrant beta-catenin and cyclin D1 expression. The expression of Pin1, beta-catenin and cyclin D1 were examined in the specimens of 65 patients with SACC by immunohistochemistry, protein and mRNA expressions were detected by western blotting and RT-PCR in four SACC cell lines. Pin1 was overexpressed in 51 cases of SACC (78%), and high levels of Pin1 expression correlated with cyclin D1 positive expression (p = 0.02). Fourteen (22%) cases showed positive immunoreactivity for beta-catenin protein in the nuclear/cytoplasmic fraction in tumor tissues, which was defined as cytoplasm/nucleus staining, among which quite evident nuclear expression of beta-catenin was detected in six cases (9%), while cyclin D1 positive expression was detected in 41 cases of SACC (63%). Reduced membranous expression of beta-catenin was detected in the cases with metastasis (11/14). Theses results suggest that Pin1 and Wnt signalling pathway are activated in SACC and may play a pivotal role in SACC carcinogenesis and metastasis.

Adult↗

PubMed2006

[Study on the coinfection status of Borrelia burgdorferi sensu lato and spotted fever group Rickettsia in ticks from Hunchun, Jilin province].

OBJECTIVE: To understand the coinfection status of Borrelia burgdorferi sensu lato (B.b.s.l) and spotted fever group Rickettsia (SFGR) in Hunchun of Jilin province, China. METHODS: Polymerase chain reaction (PCR) was used to detect the 5S-23S rRNA intergenic spacer of B. b. s. l and ompA of SFGR in ticks was collected in Hunchun,Jilin province. The amplification products of positive ticks were sequenced, and phylogenetic analysis was conducted by PHYLIP software package. RESULTS: The infection rate of B. b. s. l was 36.0% in Ixodes persulcatus ticks and the SFGR was discovered in I. persulcatus ticks,with an infection rate of 2.0%. The coinfection rate of both agents was 2.0%. In 327 Dermacentor siltarum ticks, the positive rates of B. b. s. l and SFGR were 30.9% and 29.1% respectively. 55 ticks (16.8%) were coinfected with the two pathogens. The sequence analysis of B. b. s. l showed that the B. b. s. l in Jilin area, which were highly homologous, all belonged to B. garinii genotypes. The sequence analysis of SFGR positive products showed that the DNA secquence of the newly detected agent (JL-95) was close to the two previously described rickettsiae which were detected in I. ricinus from Slovakia (called IRS3 and IRS4). Phylogenetic relationships inferred from the comparison of these sequences with those of other genus Rickettsiae indicated that JL-95, IRS3 and IRS4 constituted a new rickettsial genotype and formed a separate cluster among the spotted fever group Rickettsiae. CONCLUSION: Coinfection of B. b. s. l and SFGR existed in Hunchun, Jilin province. The sequencing of specific fragment confirmed a new SFGR which was different from other rickettsiae known in China.

Animals↗

PubMed2006

[C-reactive protein induced human endothelium cells apoptosis is associated with Bcl-2/Bax gene expression changes].

OBJECTIVE: In the present study, we examined the expression changes of Bcl-2/Bax in C-reactive protein (CRP) treated human endothelium cells in vitro. METHODS: The human umbilical vein endothelial cells (HUVEC) were cultured by digest method for 2 - 3 posterities and incubated with human CRP (0, 1, 5, 25 mg/L for 24 hours) and analyzed by flow cytometer for apoptosis ratio. The effects of CRP in various concentrations on Bcl-2/Bax mRNA and protein expression were examined by RT-PCR and Western Blotting. RESULTS: Apoptosis ratio increased, downregulated Bcl-2 (gene promoting cell survival) and upregulated Bax (gene promoting apoptosis) at mRNA and protein levels in proportion to increased CRP concentrations. CONCLUSION: These results demonstrate that Bcl-2/Bax could be regulated by CRP in human HUVECs and might play a causal role in CRP-induced apoptosis.

Apoptosis↗

PubMed2006

[An in vitro study on the incidence of the second mesiobuccal canal in the mesiobuccal root of the first and second maxillary molars].

OBJECTIVE: To investigate the incidence of the second mesiobuccal canal (MB2) in the mesiobuccal root of the maxillary first and second molars in Chinese population using three techniques, including the clearing technique, spiral CT scanning and serial root sections. METHODS: A total of 216 extracted human first and 334 second maxillary molars were randomly divided into two groups respectively: group A and B. The teeth in group A were cleared. The specimens in group B were subjected to spiral CT scanning, and then the roots were cross-sectioned every 1 mm from the root apex. Under the Dental operating microscope (DOM), the incidence of MB2 were recorded. RESULTS: (1) The incidence of MB2 in the first and the second maxillary molars were 81.48% and 49.70% respectively by clearing, and 77.78% and 47.31% from S-CT scanning, 88.89% and 53.89% respectively from serial root section. The occurrence of MB2 in maxillary first molars was statistically higher than in maxillary second molars (P < 0.05, chi square test). (2) There was no significant difference among the three approaches for detecting the MB2 canal (P > 0.05, chi square test). CONCLUSIONS: Both the maxillary first molars and the second molars have high incidence of MB2.

Dental Pulp Cavity↗

PubMed2006

[Expression of Pin1, beta-catenin and cyclin D1 in salivary adenoid cystic carcinoma and its significance].

OBJECTIVE: To investigate the expression of Pin1, beta-catenin and cyclin D1 in salivary adenoid cystic carcinomas (SACC) and to evaluate the role of beta-catenin and Pin1 in SACC carcinogenesis. METHODS: The expressions of Pin1, beta-catenin and cyclin D1 were examined in the specimens of 65 patients with SACC by immunohistochemistry, and Pin1 protein and mRNA expressions detected by Western blot and RT-PCR in four SACC cell lines. RESULTS: Pin1 was overexpressed in 51 cases of ACC (78%), and 41 (63%) cases showed positive immunoreactivity for cyclin D1 protein in the nuclear fraction in tumor tissues. Fourteen (22%) cases showed positive immunoreactivity for beta-catenin protein in the nuclear/cytoplasmic fraction in tumor tissues, 6 of which exhibited quite evident expression of beta-catenin in nucleolus. The expression of membranous beta-catenin was down-regulated in most of the patients with lymph node metastasis (11/14). CONCLUSIONS: The results suggest that Pin1 and beta-catenin signalling pathway were activated in SACC and might play a pivotal role in SACC carcinogenesis and metastasis.

Carcinoma, Adenoid Cystic↗

PubMed2006

[Investigation on Borrelia burgdorferi sensu lato in ticks and rodents collected in Da Xing-An Mountains Forest areas of China].

OBJECTIVE: To detect and study the types of Borrelia burgdorferi sensu lato in ticks and rodents from Da Xing-An Mountains Forest areas of China. METHODS: Nested PCR was performed to amplify 5S-23S rRNA intergenic spacer of B. burgdorferi. Positive products were analysed by restriction fragment length polymorphism (RFLP) and single strand conformation polymorphism (SSCP), specimens showing unique RFLP profile were sequenced and analysed. RESULTS: 1336 Ixodes persulcatus, 144 Dermacento silvarum, 144 Haemaphysalis concinna and 145 rodents of 9 species were collected from 16 sections of Da Xing-An Mountains Forest areas of China. Specific fragments were amplified from 293 I. persulcatus and 6 D. silvarum and 5 rodents of 4 species. B. burgdorferi was not detected in H. concinna. Among the positively tested I. persulcatus, 209 contained B. garinii genospecies and 45 contained B.afzelii genospecies based on RFLP. Moreover, B.garinii genospecies consisted of B. garinii 20047 and B. garinii NT29. 17 adult I. persulcatus were simultaneously infected with B. garinii 20047 and B. garinii NT29. Nine adult I. persulcatus were simultaneously infected with B. garinii 20047 and B. afzelii. Four adult I. persulcatus were simultaneously infected with B. garinii 20047 and B. garinii NT29 and B. afzelii. Two D. silvarum were infected with B. garinii 20047, 1 D. silvarum with B. garinii 20047, 2 D. silvarum with B. afzelii. 3 rodents were infected with B. garinii 20047 while 2 rodents were infected with B. garinii NT29. Mixed infection was not found in D. silvarum and rodents. In addition, nine I. persulcatus and one D. silvarum specimens showed unique RFLP pattern. Data from sequential analysis showed that they all belonged to B. garinii. PCR-SSCP profiles of 5S-23S rRNA intergenic spacer of B. burgdorferi in the positive specimens exceeded 36 types; B. garinii 20047 showed 16 types while B. garinii NT29 showing 11 types, B. afzelii showing 9 types. SSCP profiles of the specimens coinfected with multiple B. burgdorferi was relatively complex. CONCLUSION: The infection of B. burgdorferi was found in the ticks and rodents in Da Xing-An Mountains Forests areas. The infection rate of I. persulcatus was high. B. garinii was predominant genospecies, and the population of B. burgdorferi was heterogeneous in the area. Mixed infections of different B. burgdorferi genospecies in ticks were found. I. persulcatus and Clethrionomys rufocanus were possibly served as major vector and major host for B. burgdorferi, respectively, suggesting that further study is needed to confirm the coinfection in humans and animals in this region.

Animals↗

PubMed2005

Protein phosphatase-1 inhibitor-3 is co-localized to the nucleoli and centrosomes with PP1gamma1 and PP1alpha, respectively.

In this study, we show that protein phosphatase-1 (PP1) inhibitor-3 (Inh3) is localized to the nucleoli and centrosomes in interphase HEK 293 cells. Inh3 exhibited a specific co-localization to the nucleoli with PP1gamma1, and to the centrosomes with PP1alpha. These findings indicate that Inh3 may act as a modulator of PP1 functions in the processes of cytokinesis, as well as of nucleolar events. The specificity of the interaction of Inh3 with the PP1 isoforms was also demonstrated in vitro, where Inh3 co-immunoprecipitated with PP1alpha and PP1gamma1, but not with PP1beta. The nuclear localization signal of Inh3 was identified as a N-terminal basic cluster (33RKRK36), while nucleolar localization was shown to be dependent on a C-terminal basic cluster (94HRKGRRR100). The importance of the individual basic residues was quantitatively assessed by site-directed mutagenesis and a novel use of laser scanning cytometry.

Binding Sites↗

PubMed2005

Low-temperature growth and photoluminescence property of ZnS nanoribbons.

At a low temperature of 450 degrees C, ZnS nanoribbons have been synthesized on Si and KCl substrates by a simple chemical vapor deposition (CVD) method with a two-temperature-zone furnace. Zinc and sulfur powders are used as sources in the different temperature zones. X-ray diffraction (XRD), selected area electron diffraction (SEAD), and transmission electron microscopy (TEM) analysis show that the ZnS nanoribbons are the wurtzite structure, and there are two types-single-crystal and bicrystal nanoribbons. Photoluminescence (PL) spectrum shows that the spectrum mainly includes two parts: a purple emission band centering at about 390 nm and a blue emission band centering at about 445 nm with a weak green shoulder around 510 nm.

Journal Article↗

PubMed2005

Plasma homocysteine thiolactone adducts associated with risk of coronary heart disease.

BACKGROUND: Homocysteine thiolactone adducts have been proposed as the culprit of homocysteine related cardiovascular diseases. We studied the association of these adducts in plasma, and the gene polymorphism of paraoxonase-2 with coronary heart disease. METHODS: 254 patients and 308 controls were recruited for the study. Homocysteine thiolactone adducts were determined with ELISA. The codon 311 polymorphism of paraoxonase-2 gene was genotyped by using polymerase chain reaction and restrictive digestion. RESULTS: The plasma level of homocysteine thiolactone adducts were significantly higher in patients than in controls (40.65 +/- 10.87 u/ml vs. 30.58 +/- 10.20 u/ml, P <0.01), with odds ratio of 7.34 (95% confidence interval 4.020-13.406, P <0.01), and increased according to the number of atherosclerotic coronary arteries: 35.59 +/- 10.34 units/ml (n = 76); 41.88 +/- 8.83 (n = 70) and 43.13 +/- 11.47 (n = 108) in subjects with 1, 2 and 3 affected arteries, respectively (r =0.174, P < 0.01). The frequency of CC genotype was significantly higher in patients with coronary heart disease (7.48%) than in controls (1.62%, P < 0.01), with adjusted odds ratio of 4.367 (95% confidence interval: 1.178 to 16.191, P < 0.01), so was the C allele (23.2% vs. 14.9%, P < 0.05). CONCLUSIONS: High plasma homocysteine thiolactone adducts and the CC 311 genotype of paraoxonase-2 gene may be the emerging risk factor for coronary heart disease.

Adult↗

PubMed2005

Transfusion of multi-factors activated immune cells as a novel treatment for patients with chronic hepatitis B.

BACKGROUND AND OBJECTIVES: Host-virus interactions play a central role in determining the prognosis of hepatitis B virus infection. Multi-factors activated immune cells (MAICs) are autologous peripheral blood mononuclear cells activated with anti-CD3 monoclonal antibody, interleukin-2 and interferon-gamma. The present pilot clinical trial was designed to determine whether adoptively transferred MAICs inhibit the replication of hepatitis B virus and is safe for patients. STUDY DESIGN: Fourteen patients with chronic hepatitis B were enrolled in the study. A total of (1.5-4.0)x10(9) peripheral blood mononuclear cells were isolated from each patient and activated by anti-CD3 monoclonal antibody, interleukin-2 and interferon-gamma in vitro for 10 days to produce MAICs. Cell phenotypes and levels of cytokine secretion were determined during cell culture. Patients were followed up for 1 year after the transfusion of MAICs. RESULTS: After 10 days of culture, peripheral blood mononuclear cells were expanded to a mean fold of 4.68+/-1.78 and activated effectively, as demonstrated by CD25 expression and cytokine secretion. Cell activation peaked on day 4. All patients accepted the MAICs transfusion with some slight adverse events, and fulminant hepatitis and bilirubinemia were not observed. Significant HBV inhibition was observed in 8 out of 14 patients, in which 5 patients achieved complete response (defined as that serum HBV DNA levels below the detection limit, occurrence of HBeAg seroconversion and normalization of ALT were observed together after MAICs transfusion and kept for at least 6 months) and 3 patients achieved partial response (defined as that serum HBV DNA levels below the detection limit, occurrence of HBeAg disappearance and normalization of ALT were observed together in 6 months after MAICs transfusion, but kept for less than 6 months). CONCLUSION: These findings strongly suggest that MAICs transfusion, which effectively inhibits the replication of hepatitis B virus, is safe for patients.

Adolescent↗

PubMed2005

An identity crisis for fps/fes: oncogene or tumor suppressor?

Fps/Fes proteins were among the first members of the protein tyrosine kinase family to be characterized as dominant-acting oncoproteins. Addition of retroviral GAG sequences or other experimentally induced mutations activated the latent transforming potential of Fps/Fes. However, activating mutations in fps/fes had not been found in human tumors until recently, when mutational analysis of a panel of colorectal cancers identified four somatic mutations in sequences encoding the Fps/Fes kinase domain. Here, we report biochemical and theoretical structural analysis demonstrating that three of these mutations result in inactivation, not activation, of Fps/Fes, whereas the fourth mutation compromised in vivo activity. These results did not concur with a classic dominant-acting oncogenic role for fps/fes involving activating somatic mutations but instead raised the possibility that inactivating fps/fes mutations might promote tumor progression in vivo. Consistent with this, we observed that tumor onset in a mouse model of breast epithelial cancer occurred earlier in mice targeted with either null or kinase-inactivating fps/fes mutations. Furthermore, a fps/fes transgene restored normal tumor onset kinetics in targeted fps/fes null mice. These data suggest a novel and unexpected tumor suppressor role for Fps/Fes in epithelial cells.

Animals↗

PubMed2005

Transgenic zebrafish that express tyrosine hydroxylase promoter in inner retinal cells.

We have generated a transgenic zebrafish line [Tg(Th:GFP)] that expresses green fluorescence proteins (GFP) driven by rat tyrosine hydroxylase (TH) promoter. In zebrafish, the transgene was expressed as early as 16 hr postfertilization (hpf). The first transgene expression was detected in the midbrain. Within a few hours of development, the expression spread to the forebrain and hindbrain. In the retina, the first transgene expression was detected at approximately 40 hpf, at which time a single GFP-positive cell was seen in the ventral-nasal patch of the retina. In late development, GFP spread across the inner retina. GFP was found in retinal cells that expressed TH or phenylethanolamine N-methyl-transferase (PNMT), the first and last enzymes for synthesis of catecholamine, respectively. This suggests that the transgene is expressed in catecholaminergic neurons. Of interest, GFP was also detected in some retinal cells that release gamma-aminobutyric acid. These latter data suggest that the transgene may also be expressed in noncatecholaminergic cells.

Animals↗

PubMed2005

Chiral separations on multichannel microfluidic chips.

Chiral separations of FITC-labeled basic drugs on multichannel microfluidic chips with LIF detector were investigated. A preliminary screening procedure for seven neutral CDs was performed under optimized conditions for chiral separations of three FITC-labeled drugs (baclofen, norfenefrine, and tocainide) on a mono-channel microfluidic chip. According to the results of screening, FITC-baclofen and FITC-norfenefrine as well as two chiral selectors including gamma-CD and dimethyl-beta-CD (DM-beta-CD) were selected as models to perform chiral separations on a two-channel chip. FITC-baclofen enantiomers were separated completely by gamma-CD in one channel, while resolution of FITC-norfenefrine enantiomers was achieved by DM-beta-CD in the other channel in the same run. Furthermore, the feasibility of using one chiral selector to separate multiple chiral samples was studied on a four-channel chip. These results show that multichannel chip has a potential for chiral high-throughput screening.

Baclofen↗

PubMed2005

Synthesis of long indium nitride nanowires with uniform diameters in large quantities.

Large quantities of indium nitride (InN) nanowires are synthesized by the in situ nitriding of indium oxide (In(2)O(3)) powders in an ammonia (NH(3)) flux. Tens of milligrams of nanowires are obtained in one batch. Every 100 mg of In(2)O(3) starting powder can produce up to 65 mg of InN nanowires under the optimized conditions. The synthesized nanowires grow along the [001] direction with excellent crystallinity. They are of high purity and are 30-50 microm in length with an almost uniform diameter of about 100 nm. Photoluminescence measurements of the nanowires exhibit a strong peak at 707 nm. An optical bandgap of about 1.7 eV is estimated based on the absorption spectrum. The experimental results also demonstrate that the approach of nitriding In(2)O(3) powders in situ is feasible for the synthesis of high-purity InN nanowires in large quantities, with good reproducibility and without catalyst materials. The synthesis of InN nanowires in large quantities would be of benefit to the further study and understanding of their intrinsic properties, as well as being advantageous for their potential application in nanodevices.

Indium↗

PubMed2005

Programmable assembly of nanoarchitectures using genetically engineered viruses.

Biological systems possess inherent molecular recognition and self-assembly capabilities and are attractive templates for constructing complex material structures with molecular precision. Here we report the assembly of various nanoachitectures including nanoparticle arrays, hetero-nanoparticle architectures, and nanowires utilizing highly engineered M13 bacteriophage as templates. The genome of M13 phage can be rationally engineered to produce viral particles with distinct substrate-specific peptides expressed on the filamentous capsid and the ends, providing a generic template for programmable assembly of complex nanostructures. Phage clones with gold-binding motifs on the capsid and streptavidin-binding motifs at one end are created and used to assemble Au and CdSe nanocrytals into ordered one-dimensional arrays and more complex geometries. Initial studies show such nanoparticle arrays can further function as templates to nucleate highly conductive nanowires that are important for addressing/interconnecting individual nanostructures.

Bacteriophage M13↗

PubMed2005

Ameloblastic fibroma and related lesions: a clinicopathologic study with reference to their nature and interrelationship.

BACKGROUND: Ameloblastic fibroma (AF) and related lesions constitute a group of lesions, which range in biologic behavior from true neoplasms to hamartomas. The aim of this study was to elucidate the nature and interrelationship of this group of lesions. METHODS: Clinical and pathological studies were undertaken retrospectively on 13 cases of AF and seven cases of ameloblastic fibro-odontoma (AFO). Thirty-three complex odontomas and 33 compound odontomas were also included for comparative purpose. Relevant follow-up data were recorded and the literature was reviewed. RESULTS: The majority of patients with AF (nine cases, 69.2%) were over the age of 22 years with frequent involvement (76.9%) of the posterior mandible. Tumors recurred in four of 11 patients with follow-up information and two recurrent tumors showed malignant transformation. There was no case in this series that could be designated as the so-called ameloblastic fibrodentinoma, apart from one recurrent AF in which further maturation to form only tubular dentin materials was identified. AFO tended to occur at a younger age group with an average of 9.6 years. Recurrence was noted in two of five patients with follow-up data and both recurrent lesions showed limited growth potential and further maturation into a complex odontoma. Significant differences were noted in the age and site distribution between the complex and the compound odontomas. CONCLUSION: Whilst the majority, if not all, of AFs are true neoplasms with a potential to recur and/or of malignant transformation, some, especially those occurred during childhood, could represent the primitive stage of a developing odontoma. Our data also suggests that some AFOs are hamartomatous in nature, representing a stage preceding the complex odontoma.

Adolescent↗

PubMed2005

Circadian rhythms of behavioral cone sensitivity and long wavelength opsin mRNA expression: a correlation study in zebrafish.

Using a behavioral assay based on visually mediated escape responses, we measured long-wavelength-sensitive red cone (LC) sensitivities in zebrafish. In a 24 h period, the zebrafish were least sensitive to red light in the early morning and most sensitive in the late afternoon. To investigate if the fluctuation of behavioral cone sensitivity correlates with opsin gene expression, we measured LC opsin mRNA expression at different times in the day and night under different lighting conditions. Under a normal light-dark cycle, the expression of LC opsin mRNA determined by real-time RT-PCR was low in the early morning and high in the late afternoon, similar to the fluctuation of behavioral cone sensitivity. This rhythm of LC opsin mRNA expression, however, dampened out gradually in constant conditions. After 24 h of constant light (LL), the expression of LC opsin mRNA dropped to levels similar to those determined in the early morning in control animals. By contrast, when the zebrafish were kept in constant dark (DD), the expression of LC opsin mRNA increased, to levels about 30-fold higher than the expression in the early morning in control animals. This day-night fluctuation in LC opsin mRNA expression was correlated to changes in opsin density in the outer segment of cone photoreceptor cells. Microspectrophotometry (MSP) measurements found significant differences in red cone outer segment optical density with a rhythm following the behavioral sensitivity. Furthermore, dopamine modulated the circadian rhythms in expression of LC opsin mRNA. Administration of dopamine increased LC opsin mRNA expression, but only in the early morning.

Animals↗