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Biomedical subjects

Yan Yang

Publications and source records attributed to Yan Yang.

At least 55 records · Page 3Linked to original sources
PubMed2006

[The effects of remain of residual tooth on retention of post-core crown system].

This study was aimed to assess the effects of remain of residual tooth on the retention of postpost-core was made,casted and cemented. The post-core was tested at the speed of 10 mm/min on the Instron4302, and the retention force was recorded. Other samples were made and subjected to the test for cohesion of polymethylmethacrylate and metal. The result showed that retention significantly increased with the adding of the residual tooth. When the length of post was longer than 8 mm and 1 mm was added to tooth remain, the difference in retention between the two groups was statistically significant. It was noted that there existed relationships of retention to length of post and tooth remain, of cohesion to length of post and tooth remain, and of frictiion resistence to length of post and tooth remain; moreover, the relevant linear regression equations were obtained. So during the tooth preparation of post-core system, the tooth tissue should be reserved as much as possible.

Crowns↗
PubMed2006

[Influence of lipopolysaccharide and burn sera on ion channels in smooth muscle cells of colon of guinea pig].

OBJECTIVE: To investigate the influence of lipopolysaccharide (LPS) and burn sera on potassium channels (Kca) in smooth muscle cells of colon of guinea pig so as to elucidate the molecular mechanism of gastrointestinal motility dysfunction after severe burns. METHODS: Single smooth muscle cells were isolated from the taenia coli of guinea pig with enzyme digestion. The standard patch clamp technique was employed to record the single KCa channel currents of smooth muscle cell after challenged by LPS and burn serum. Data were recorded and analyzed by P clamp 6.04 software, and the probability of open (PO), mean open time (OT), mean close time (CT) and current amplitude (CA) were determined. Subsequently, LPS in the concentration of 20, 40, 60, 80 and 100 mg/L, respectively, and normal serum and burn serum in the concentration of 10% were respectively added into medium to examine the influence of the two clamps and sera on the KCa activity. RESULTS: In hyperkalemic solution, the KCa conductance of colonic smooth muscle cells of the guinea pig was (271 +/- 7) pS, indicating it was an ionic channel with high conductivity. Subsequent to depolarization of the membrane, inner-cellular calcium level was increased, and channel PO was also increased, which could be blocked by 1 mmol/L tetraethylammonium (TEA) outside the membrane chaff. As 40 mmol/L TEA inside the membrane chaff did not show such effect, it was proved to be KCa current. The activity of the channel as determined with two kinds of clamps was increased in a dose dependent manner with LPS challenge when the concentration of calcium was 0 mol/L. The KCa activity and PO of the channel was increased obviously when the concentration of LPS was above 40 mg/L (P < 0.05 or 0.01), and it could not be reversed after irrigation with non-LPS medium. By using the two kinds of patch clamps, the KCa were activated by burn sera, but not normal sera. CONCLUSION: Both LPS and burn sera can lead to inhibition of the gastrointestinal motility by activation of KCa channels.

Animals↗
PubMed2006

[Study on the relationship between TCM syndrome and gastroscopic feature in children with stomachache].

OBJECTIVE: To explore the characteristic of TCM syndrome in children with stomachache and its relationship with the gastroscopic feature. METHODS: The relationship between macroscopic syndrome differentiation and microscopic syndrome differentiation in 300 children with stomachache was analyzed by means of clinical syndrome differentiation and gastroscopic examination. RESULTS: The total disease detectable rate of gastroscopic examination was 98.3%. Dampness-heat syndrome and deficiency-cold syndrome were the syndromes that most commonly be detected by either macroscopic or microscopic syndrome differentiation. And the two methods of differentiation showed better coherence in superficial gastritis. CONCLUSION: The clinical effect of TCM therapy on children stomachache could be improved through integrative Chinese and Western medical approach, by conducting syndrome differentiation referring to the gastroscopic features, which could conduct microscopic guidance to the clinical macroscopic syndrome differentiation.

Abdominal Pain↗
PubMed2006

[Clinical research on effects of yunpi zhixie granule in children with diarrhea].

OBJECTIVE: To investigate the clinical effect of Yunpi Zhixie Granule (YZG) on children's diarrhea. METHODS: Three hundred diarrhea cases were randomly divided into two groups equally, the treated group treated by YZG orally and the control group by smacta, both for 7 days. The clinical efficacy was observed, routine scatologic analysis, scatologic cultivation, rotavirus antigen and urinary D-xylose content were detected. RESULTS: Clinical results showed the effective rate in treating the chronic or Pi-deficiency diarrhea as well as the negative conversion rate and improvement rate of routine scatologic analysis were all higher in the treated group than those in the control group (P < 0.05); while no significant difference was found in negative conversion rate of scatologic cultivation and rotavirus antigen and urinary D-xylose content after treatment, compared with those before treatment (P > 0.05). CONCLUSION: YZG was effective in treating children' s diarrhea, especially on chronic diarrhea and diarrhea of Pi-deficiency type.

Administration, Oral↗
PubMed2005

[Microarray DNA chip in analyzing the association between HLA-DRB and advanced hepatosplenic schistosomiasis].

OBJECTIVE: To explore possible associations between host polymorphism of HLA class II genotypes and advanced hepatosplenic schistosomiasis japonica. METHODS: 45 advanced schistosomiasis patients (experimental group) and 44 age- and sex-matched patients with chronic schistosomiasis (control group) from the same area were investigated for their HLA class II gene DRB genotypes by genotyping the alleles using microarray DNA chip. The correlation of allele frequencies to advanced hepatosplenic schistosomiasis was compared for the two groups. RESULTS: HLA-DRB1*04x exhibited markedly higher frequency in advanced patients than that in control group (P < 0.01, RR = 3.928). In contrast, the frequency of HLA-DRB1*15x in advanced patients was much lower when compared with that in control group (P < 0.01, RR = 0.050). Besides, the significant allele HLA-DRB1*15x displayed concurrence with allele DRB5*010x/020x. The linked gene haplotype DRB1*15x-DRB5*010x/020x showed significantly higher incidence in control group than in experimental group (P < 0.01). CONCLUSION: Allele HLA-DRB1*04x is positively, while HLA-DRB1*15x is negatively, correlated with advanced hepatosplenic schistosomiasis.

Adult↗
PubMed2005

A rostrocaudal muscular dystrophy caused by a defect in choline kinase beta, the first enzyme in phosphatidylcholine biosynthesis.

Muscular dystrophies include a diverse group of genetically heterogeneous disorders that together affect 1 in 2000 births worldwide. The diseases are characterized by progressive muscle weakness and wasting that lead to severe disability and often premature death. Rostrocaudal muscular dystrophy (rmd) is a new recessive mouse mutation that causes a rapidly progressive muscular dystrophy and a neonatal forelimb bone deformity. The rmd mutation is a 1.6-kb intragenic deletion within the choline kinase beta (Chkb) gene, resulting in a complete loss of CHKB protein and enzymatic activity. CHKB is one of two mammalian choline kinase (CHK) enzymes (alpha and beta) that catalyze the phosphorylation of choline to phosphocholine in the biosynthesis of the major membrane phospholipid phosphatidylcholine. While mutant rmd mice show a dramatic decrease of CHK activity in all tissues, the dystrophy is only evident in skeletal muscle tissues in an unusual rostral-to-caudal gradient. Minor membrane disruption similar to dysferlinopathies suggest that membrane fusion defects may underlie this dystrophy, because severe membrane disruptions are not evident as determined by creatine kinase levels, Evans Blue infiltration, and unaltered levels of proteins in the dystrophin-glycoprotein complex. The rmd mutant mouse offers the first demonstration of a defect in a phospholipid biosynthetic enzyme causing muscular dystrophy, representing a unique model for understanding mechanisms of muscle degeneration.

Animals↗
PubMed2005

A microtubule associated protein (hNUDC) binds to the extracellular domain of thrombopoietin receptor (Mpl).

Human NUDC (hNUDC) was initially characterized as a nuclear migration protein based on the similarity of its C-terminus to that of fungal NUDC from Aspergillus nidulans. However, hNUDC is a 331 amino acid protein whereas fungal NUDC is 198 amino acids in length. The extra N-terminal portion of hNUDC has no known function or homology to other proteins. In this study, we report the binding of hNUDC to the extracellular domain of the thrombopoietin receptor (Mpl) as detected by the yeast two-hybrid system, GST pull-down, and co-immunoprecipitation. Our deletion analysis demonstrated that amino acids between positions 100 and 238 as the critical domain mediating the hNUDC and Mpl interactions as detected by the two-hybrid system and GST pull-down assay. Immunofluorescence staining of human megakaryocyte cells indicated that hNUDC and Mpl colocalized at all stages of megakaryocyte development. Substantial colocalization of hNUDC with microtubules was also detected around nuclei and elongated microtubular structures, especially in proplatelet extensions.

Blotting, Western↗
PubMed2005

Preparation and characterization of uniform nanosized cephradine by combination of reactive precipitation and liquid anti-solvent precipitation under high gravity environment.

In this work, a novel direct method, which was combined with reactive precipitation and liquid anti-solvent precipitation under high gravity environment, had been developed to prepare nanosized cephradine with narrow particle size distribution. Compared with commercial crude cephradine, the prepared cephradine showed a significant decrease in particle size, a significant increase in the specific surface area and shorter dissolving time when used for injection. The characteristic particle size was between 200-400 nm. The specific surface area increased from 2.95 to 10.87 m2/g after micronization. When the amount of L-arginin decreased from 0.25 to 0.18 g, the mixture of nanosized cephradine and L-arginine could still dissolve in 1 min. The X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) analysis indicated that the physical characteristics and molecular states remained unchanged after the recrystallization process. This method had potential application in industrial fields because of its low cost, efficient processing and the ease of scaling-up.

Cephalosporins↗
PubMed2005

Unexpected amino acid composition of modern Reptilia and its implications in molecular mechanisms of dinosaur extinction.

Dinosaur extinction is a great challenge to evolutionary biology. Although accumulating evidence suggests that an abrupt change of environment, such as a long period of low temperature induced by asteroid hit or other disasters, may be responsible for dinosaur extinction, little is known about the underlying molecular mechanisms. By analyzing the amino acid compositions of 13 biological classes, we found that the charged amino acid content of modern Reptilia, the sibling of dinosaur, is strikingly different from those of other classes, which inspires us to propose a possible molecular mechanism for dinosaur extinction.

Amino Acid Sequence↗
PubMed2005

[Effect of IP3 on BK channels of porcine coronary artery smooth muscle cells].

D-myo-inositol 1,4,5-trisphosphate (IP(3)) plays an important role in signal transduction. It releases Ca(2+) from intracellular sites, which activates the Ca(2+)-dependent channels such as large-conductance Ca(2+)-activated potassium channels (BK channels). The present study was therefore designed to determine if the activity of BK channels in porcine coronary artery smooth muscle cells was increased by IP(3). Using the inside-out patch-clamp technique, the activity of single BK channels was recorded in porcine coronary artery smooth muscle cells. In excised inside-out membrane patches, IP(3) (10-50 micromol/L) enhanced the open probability (Po) of BK channels in a dose-dependent manner in the intracellular side of inside-out patches and its effect was almost completely abolished by washout. The open-state probability of the BK channels increased from a control level of 0.0402+/-0.0152 to 0.1365+/-0.0212 (20 micromol/L IP(3)) and 0.1865+/-0.0175 (30 micromol/L IP(3)). IP(3) decreased the mean close time markedly, but had no effect on the amplitude of BK channels. The activation of IP(3) on BK channels did not decline. The metabolite of IP(3) had no obvious effect on BK channels. This study provides evidence that IP(3) activates BK channels in porcine coronary artery smooth muscle cells in a dose-dependence manner.

Animals↗
PubMed2005

[Therapeutic effects of combination of arsenic trioxide with low-dose all-trans retinoic acid on induction of remission acute promyeloeytic leukemia].

OBJECTIVE: To observe the therapeutic efficacy and side effects of arsenic trioxide (As2O3)combined with low-dose all-trans retinoic acid (ATRA) on remission induction in newly-diagnosed and relapsed patients with acute promyeloeytic leukemia (APL). METHODS: 224 patients of APL, 156 newly diagnosed patients, aged 34 (13 approximately 62), with a male/female ratio of 1.56, and 28 relapsed patients, aged, aged 34 (12 approximately 63), with a male/female ratio of 1.89, underwent As2O3 + ATRA therapy. The therapeutic effects was compared with that of As2O3 alone treatment on 40 newly diagnosed patients and 25 relapsed patients and that of ATRA alone treatment on 36 newly diagnosed patients and 15 relapsed patients. The treatment protocol for the combination group was as following: As2O3 was administered intravenously at a dose of 10 mg/day and ATRA was given orally three times per day at a dose of 10 mg. The complete remission (CR) rate, period to CR, incidence of early death and side effects were observed in the three groups. RESULTS: In the newly-diagnosed patients, there was no significant difference in CR rate among the three groups (92.5% for the As2O3/LD-ATRA group, 83.8% for the ATRA group, and 90% for the As2O3 group respectively). In comparison with As2O3 alone, administration of LD-ATRA to the patients in the As2O3/LD-ATRA group significantly shortened the period to CR (the medium time to CR was 28 days for the As2O3/LD-ATRA group and 39 days for the As2O3 group respectively). As compared to ATRA alone, treatment with As2O3 with low-dose ATRA showed a significantly lower incidence of early death (2.5% for the As2O3/LD-ATRA group and 13.9% for the ATRA group respectively). In the relapsed patients, the CR rate was significantly higher in the group treated with As2O3/LD-ATRA (71.4% for the As2O3/LD-ATRA group, 32.0% for the ATRA group, and 43.0% for the As2O3 group respectively). The combined use of LD-ATRA with As2O3 did not further enhance toxic side effects as compared to As2O3 alone or ATRA alone. CONCLUSION: As2O3/LD-ATRA regimen is superior to either regimen given alone to patients with APL. It is an efficient therapeutic approach to APL patients using a combination of As2O3 with low-dose ATRA.

Adolescent↗
PubMed2005

The dynamics of hippocampal sensory gating during the development of morphine dependence and withdrawal in rats.

The effects of morphine on hippocampal sensory gating (N40) during the development of morphine dependence and withdrawal were investigated in the double click auditory evoked potential (EP) suppression paradigm. Rats were made dependent upon morphine hydrochloride by a series of injections (every 12 h) over 6 days, followed by withdrawal after stopping morphine administration. Hippocampal gating was examined during the development of dependence and withdrawal. Moreover, the DA antagonist haloperidol was used to assess the contribution of dopamine to hippocampal gating induced by morphine. Our results showed that the morphine-treated rats exhibited significantly disrupted hippocampal gating during the development of morphine dependence and this disrupted gating was partially reversed by haloperidol pretreatment. In contrast, there was significantly enhanced hippocampal gating at the fifth and sixth days of withdrawal. The dynamics of hippocampal gating during the development of morphine dependence and withdrawal suggests the interaction between the hippocampus and opioids.

Acoustic Stimulation↗
PubMed2005

Loss of neuronal cell cycle control in ataxia-telangiectasia: a unified disease mechanism.

In ataxia-telangiectasia (A-T), the loss of the ataxia-telangiectasia mutated (ATM) kinase leads to a failure of cell cycle checkpoints and DNA double-strand break detection resulting in cellular radiation sensitivity and a predisposition to cancer. There is also a significant loss of neurons, in particular cerebellar granule and Purkinje cells. Mice homozygous for null alleles of atm reproduce the radiation sensitivity and high-tumor incidence of the human disease but show no significant nerve cell loss. Using immunocytochemistry, we found the re-expression of cell cycle proteins in Purkinje cells and striatal neurons in both human and mouse A-T. In the mouse, we used fluorescent in situ hybridization (FISH) to document that DNA replication accompanies the reappearance of these proteins in at-risk neuronal cells. We also found the presence of significant cell cycle activity in the Purkinje cells of the atm+/- heterozygote mouse. The cell cycle events in mouse cerebellum occur primarily during the third postnatal week by both FISH and immunocytochemistry. Thus, the initiation of this ectopic cell division occurs just as the final stages of Purkinje cell development are being completed. These results suggest that loss of cell cycle control represents a common disease mechanism that underlies the defects in the affected tissues in both human and mouse diseases.

Adult↗
PubMed2005

A chimeric GB virus B with 5' nontranslated RNA sequence from hepatitis C virus causes hepatitis in tamarins.

Only humans and chimpanzees are fully permissive for replication of hepatitis C virus (HCV), an important cause of liver cirrhosis and cancer worldwide. The absence of suitable animal models limits opportunities for in vivo evaluation of candidate hepatitis C therapeutics and slows progress in the field. Here, we describe a chimeric virus derived from GB virus B (GBV-B), an unclassified hepatotropic member of the family Flaviviridae that is closely related to HCV and infects tamarins (Saguinus sp.), in which a functionally important HCV regulatory sequence replaced an analogous sequence in the 5' nontranslated region (5'NTR) of the GBV-B genome. The transplanted sequence comprised domain III of the internal ribosome entry site (IRES), which directly binds the 40S ribosome subunit and is a target for candidate therapeutics. The chimeric 5'NTR retained ribosome binding activity and was competent in directing protein translation both in cell-free translation reactions and in transfected primary tamarin hepatocyte cultures. Virus rescued from the chimeric RNA replicated in the liver of tamarins, causing biochemical and histopathological changes typical of viral hepatitis. However, adaptive mutations were required elsewhere in the genome for efficient replication. Virus was not rescued from other, translationally competent, chimeric RNAs in which domain II of the IRES was exchanged. Thus, the 5'NTR appears to contain virus-specific replication signals that interact with other sites within the viral genome or with viral proteins. In conclusion, such novel chimeric flaviviruses offer opportunities for new insights into HCV replication mechanisms, while potentially facilitating the evaluation of candidate therapeutics in vivo.

5' Untranslated Regions↗
PubMed2005

Harmonic skeleton guided evaluation of stenoses in human coronary arteries.

This paper presents a novel approach that three-dimensionally visualizes and evaluates stenoses in human coronary arteries by using harmonic skeletons. A harmonic skeleton is the center line of a multi-branched tubular surface extracted based on a harmonic function, which is the solution of the Laplace equation. This skeletonization method guarantees smoothness and connectivity and provides a fast and straightforward way to calculate local cross-sectional areas of the arteries, and thus provides the possibility to localize and evaluate coronary artery stenosis, which is a commonly seen pathology in coronary artery disease.

Algorithms↗
PubMed2005

Plasma levels of the anti-inflammatory cytokine IL-10 and inflammatory cytokine IL-6 in patients with unstable angina.

The plasma levels of inflammatory cytokine interleukin-6 (IL-6) and anti-inflammatory cytokine interleukin-10 (IL-10) in the patients with unstable angina or stable angina were determined and compared. In 30 patients with unstable angina and 22 patients with stable angina, plasma levels of IL-10 and IL-6 were detected by ELISA and plasma lipid parameters by lipid research clinical methods respectively. The results showed plasma levels of IL-10 were significantly lower in unstable angina group than in stable angina group (P = 0.005), while those of IL-6 were significantly increased in unstable angina group as compared with those in stable angina group (P = 0.039). There was a significantly negative correlation between IL-10 and IL-6 in patients with unstable angina (r = -0.41, P = 0.003). In the unstable angina group, IL-6 levels were obviously positively correlated with TC (r = 0.314, P = 0.023), but not with TG and HDL. There were no significant correlations between IL-10 and plasma lipid parameters. It was suggested that the decreased IL-10 and increased IL-6 might be associated with the atheromatous plaque stability and progression of coronary heart diseases. IL-10 may play an important role in preventing coronary vascular lesions.

Angina, Unstable↗
PubMed2005

Insulin acutely decreases hepatic fatty acid synthase activity.

Insulin is viewed as a positive regulator of fatty acid synthesis by increasing fatty acid synthase (FAS) mRNA transcription. We uncover a new mechanism by which insulin acutely reduces hepatic FAS activity by inducing phosphorylation of the carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) and its interaction with FAS. Ceacam1 null mice (Cc1(-/-)) show loss of insulin's ability to acutely decrease hepatic FAS activity. Moreover, adenoviral delivery of wild-type, but not the phosphorylation-defective Ceacam1 mutant, restores the acute effect of insulin on FAS activity in Cc1(-/-) primary hepatocytes. Failure of insulin to acutely reduce hepatic FAS activity in hyperinsulinemic mice, including L-SACC1 transgenics with liver inactivation of CEACAM1, and Ob/Ob obese mice, suggests that the acute effect of insulin on FAS activity depends on the prior insulinemic state. We propose that this mechanism acts to reduce hepatic lipogenesis incurred by insulin pulses during refeeding.

Animals↗