Biomedical subjects

Jian Yang

Publications and source records attributed to Jian Yang.

At least 109 records · Page 6Linked to original sources

PubMed2005

[Research of the hemostasis effect of chitosan acetic acid solution].

The effect of chitosan with different molecular weight and deacetylation degree on blood hemostasis was tested. The experiments found evident alteration of red blood cell morphology and unusual coagglutination between erythrocytes in the anticoagulant blood which was treated by chitosan acetic acid solution. The red blood cells clot formation experiments showed that chitosan with low deacetylation degree (60%-70%) caused more red blood cells to assemble when compared versus chitosan with other deacetylation degrees. The effect of molecular weight between 10(5)-10(6) was not obvious. The thrombin time (TT), prothrombin time (PT), activated partial thromboplastin time (APTT), and concentration of fibrinogen (FIB) of blood treated by chitosan acetic acid solution were measured. The results proved that the hemostasis property of chitosan acetic acid solution was independent of the platelets and the normal "Cascade-like" coagulation pathway.

Acetic Acid↗

PubMed2005

[Elemental analysis and infrared spectra of suspended substance in the effluent from eco-biofilter].

The suspended substance (SS) in the effluent from eco-biofilters was examined by elemental analysis and infrared spectroscopy. The inorganic components of SS in D1 and S1 are more than those in D2 and S2, respectively. The IR spectra of SS is mainly composed of the adsorption of carbohydrates, protein, etc. The domninating bands near 1655, 1542 and 1240 cm(-1) are assigned to amide I, amide II and amide III respectively, and the characteristic IR absorption of protein could be one of the significant components of cell walls. The peak near 1460 cm(-1) is attributable to the bending stretching of CH1-- and CH3--. The strength of adsorption peaks in the region 1720-1200 cm(-1) for D1 is lower than that for D2, but at 1040 cm(-1) the case is reversed.

Filtration↗

PubMed2004

Phosphatidylinositol [correction] 4,5-bisphosphate signals underlie receptor-specific Gq/11-mediated modulation of N-type Ca2+ channels.

Modulation of voltage-gated Ca2+ channels via G-protein-coupled receptors is a prime mechanism regulating neurotransmitter release and synaptic plasticity. Despite extensive studies, the molecular mechanism underlying Gq/11-mediated modulation remains unclear. We found cloned and native N-type Ca2+ channels to be regulated by phosphatidylinositol [correction] 4,5-bisphosphate (PIP2). In inside-out oocyte patches, PIP2 greatly attenuated or reversed the observed rundown of expressed channels. In sympathetic neurons, muscarinic M1 ACh receptor suppression of the Ca2+ current (ICa) was temporally correlated with PIP2 hydrolysis, blunted by PIP2 in whole-cell pipettes, attenuated by expression of PIP2-sequestering proteins, and became irreversible when PIP2 synthesis was blocked. We also probed mechanisms of receptor specificity. Although bradykinin also induced PIP2 hydrolysis, it did not inhibit ICa. However, bradykinin receptors became nearly as effective as M1 receptors when PIP2 synthesis, IP3 receptors, or the activity of neuronal Ca2+ sensor-1 were blocked, suggesting that bradykinin receptor-induced intracellular Ca2+ increases stimulate PIP2 synthesis, compensating for PIP2 hydrolysis. We suggest that differential use of PIP2 signals underlies specificity of Gq/11-coupled receptor actions on the channels

1-Phosphatidylinositol 4-Kinase↗

PubMed2004

Synthesis and evaluations of pentahydroxylhexyl-L-cysteine and its dimer as chelating agents for cadmium or lead decorporation.

N-(2,3,4,5,6-pentahydroxylhexyl)-L-cysteine (4) and N,N'-di(2,3,4,5,6-pentahydroxylhexyl)-L-cystine (5) were synthesized. As antagonists of cadmium or lead intoxication, they were found to be effective by oral administration on repeated exposure. The bioassay in vivo indicated that their cadmium-mobilizing potencies are significantly superior to those of N-acetyl-L-cysteine and their lead-mobilizing properties are equivalent to those of DL-penicillamine (DL-PA). The stability constants of the Cd-4 and Cd-5 complexes or Pb-4 and Pb-5 complexes were determined by use of pH titration. The membrane permeability of compounds 4 and 5 was evaluated by transporting across the Caco-2 cell monolayer. The effect of compounds 4 and 5 on the concentrations of essential metal ions in the renal cortex is negligible in comparison with that of the group treated with lead only. The acute toxicity of compounds 4 was tested by oral gavage and the resulting LD50 value for both mice and rats is larger than 10 g kg(-1) bw. The cytogenetic effects of compound 4 were evaluated in the Ames assay, mouse bone marrow micronucleus test, and sperms shape abnormality assay, and all of them show the negative reactions.

Animals↗

PubMed2004

Morphologic and biomechanical changes of rat oesophagus in experimental diabetes.

AIM: To study morphologic and biomechanical changes of oesophagus in diabetes rats. METHODS: Diabetes was induced by a single injection of streptozotocin (STZ). The type of diabetes mellitus induced by parenteral STZ administration in rats was insulin-dependent (type I). The samples were excised and studied in vitro using a self-developed biomaterial test machine. RESULTS: The body mass was decreased after 4 d with STZ treatment. The length of esophagus shortened after 4, 7, 14 d. The opening angle increased after 14 d. The shear, longitudinal and circumferential stiffness were obviously raised after 28 d of STZ treatment. CONCLUSION: The changes of passive biomechanical properties reflect intra-structural alteration of tissue to a certain extent. This alteration will lead to some dysfunction of movement. For example, tension of esophageal wall will change due to some obstructive disease.

Animals↗

PubMed2004

Crystal structure of 3-carboxy-cis,cis-muconate lactonizing enzyme from Pseudomonas putida, a fumarase class II type cycloisomerase: enzyme evolution in parallel pathways.

3-Carboxy-cis,cis-muconate lactonizing enzymes (CMLEs), the key enzymes in the protocatechuate branch of the beta-ketoadipate pathway in microorganisms, catalyze the conversion of 3-carboxy-cis,cis-muconate to muconolactones. We have determined the crystal structure of the prokaryotic Pseudomonas putida CMLE (PpCMLE) at 2.6 A resolution. PpCMLE is a homotetramer and belongs to the fumarase class II superfamily. The active site of PpCMLE is formed largely by three regions, which are moderately conserved in the fumarase class II superfamily, from three respective monomers. It has been proposed that residue His141, which is highly conserved in all fumarase class II enzymes and forms a charge relay with residue Glu275 (both His141 and Glu275 are in adenylosuccinate lyase numbering), acts as the general base in most fumarase class II superfamily members. However, this charge relay pair is broken in PpCMLE. The residues corresponding to His141 and Glu275 are Trp153 and Ala289, respectively, in PpCMLE. The structures of prokaryotic MLEs and that of CMLE from the eukaryotic Neurospora crassa are completely different from that of PpCMLE, indicating MLEs and CMLEs, as well as the prokaryotic and eukaryotic CMLEs, evolved from distinct ancestors, although they catalyze similar reactions. The structural differences may be related to recognition by substrates and to differences in the mechanistic pathways by which these enzymes catalyze their respective reactions.

Amino Acid Sequence↗

PubMed2004

Localisation of centromeric proteins to a fraction of mouse minor satellite DNA on a mini-chromosome in human, mouse and chicken cells.

Centromeres are required for faithful segregation of chromosomes in cell division. It is not clear how centromere sites are specified on chromosomes in vertebrates. We have previously introduced a mini-chromosome, named ST1, into a variety of cell lines including human HT1080, mouse LA9 and chicken DT40. This mini-chromosome, segregating faithfully in these cells, contains mouse minor and major, and human Y alpha-satellite DNA repeats. In this study, after determining the organisation of the satellite repeats, we investigated the location of the centromere on the mini-chromosome by combined immunocytochemistry and fluorescence in situ hybridisation analysis. Centromeric proteins were consistently co-localised with the minor satellite repeats in all three cell lines. When chromatin fibres were highly stretched, centromeric proteins were only seen on a small portion of the minor satellite repeats. These results indicate that a fraction of the minor satellite repeats is competent in centromere function not only in mouse but also in human and chicken cells.

Animals↗

PubMed2004

Evolution and migration history of the Chinese population inferred from Chinese Y-chromosome evidence.

Y-chromosomes from 76 Chinese men covering 33 ethnic minorities throughout China as well as the Han majority were collected as genetic material for the study of Chinese nonrecombinant Y-chromosome (NRY) phylogeny. Of the accepted worldwide NRY haplogroups, three (haplogroups D, C, O) were significant in this sample, extending previous assessments of Chinese genetic diversity. Based on geographic, linguistic, and ethnohistorical information, the 33 Chinese ethnic minorities in our survey were divided into the following four subgroups: North, Tibet, West, and South. Inferred from the distribution of the newly found immediate ancestor lineage haplogroup O*, which has M214 but not M175, we argue that the southern origin scenario of this most common Chinese Y haplogroup is not very likely. We tentatively propose a West/North-origin hypothesis, suggesting that haplogroup O originated in West/North China and mainly evolved in China and thence spread further throughout eastern Eurasia. The nested cladistic analysis revealed in detail a multilayered, multidirectional, and continuous history of ethnic admixture that has shaped the contemporary Chinese population. Our results give some new clues to the evolution and migration of the Chinese population and its subsequence moving about in this land, which are in accordance with the historical records.

Biological Evolution↗

PubMed2004

Structural basis of the alpha1-beta subunit interaction of voltage-gated Ca2+ channels.

High-voltage-activated Ca2+ channels are essential for diverse biological processes. They are composed of four or five subunits, including alpha1, alpha2-delta, beta and gamma (ref. 1). Their expression and function are critically dependent on the beta-subunit, which transports alpha1 to the surface membrane and regulates diverse channel properties. It is believed that the beta-subunit interacts with alpha1 primarily through the beta-interaction domain (BID), which binds directly to the alpha-interaction domain (AID) of alpha1; however, the molecular mechanism of the alpha1-beta interaction is largely unclear. Here we report the crystal structures of the conserved core region of beta3, alone and in complex with AID, and of beta4 alone. The structures show that the beta-subunit core contains two interacting domains: a Src homology 3 (SH3) domain and a guanylate kinase (GK) domain. The AID binds to a hydrophobic groove in the GK domain through extensive interactions, conferring extremely high affinity between alpha1 and beta-subunits. The BID is essential both for the structural integrity of and for bridging the SH3 and GK domains, but it does not participate directly in binding alpha1. The presence of multiple protein-interacting modules in the beta-subunit opens a new dimension to its function as a multi-functional protein.

Amino Acid Sequence↗

PubMed2004

[The analysis of the factors for postoperative blood pressure recovery of aldosterone producing adenoma patients].

OBJECTIVE: To investigate the factors regarding the recovery of postoperative blood pressure of aldosterone producing adenoma (APA) patients. METHODS: Sixty-eight patients with APA were recruited and their data including retinal blood vessel by Doppler sonography, urinary trace albumin, pathological changes of renal biopsy and the adrenal tissues around the adenoma were analyzed in order to determine the correlation between these data and postoperative durative hypertension. RESULTS: Postoperative durative hypertension occurred in 14 cases (41.2%) with increased resistance of unilateral or bilateral central artery of retina, in 16 cases (66.7%) with increased level of urinary trace albumin. Fifteen cases underwent renal biopsy and all of them showed different pathological alterations, 11 cases (73.3%) of which presented with postoperative durative hypertension. The pathological changes of the adrenal tissues around the adenoma is either atrophy or non-atrophy (normal or hyperplasia), 8 cases (40%) and 10 cases (22.2%) of which showed postoperative durative hypertension, respectively. CONCLUSION: The renal pathological changes and increased resistance of retinal blood vessel are the main reasons leading to postoperative hypertension in patients with APA.

Adolescent↗

PubMed2004

Time-controlled transcardiac perfusion cross-linking for the study of protein interactions in complex tissues.

Because of their sensitivity to solubilizing detergents, membrane protein assemblies are difficult to study. We describe a protocol that covalently conserves protein interactions through time-controlled transcardiac perfusion cross-linking (tcTPC) before disruption of tissue integrity. To validate tcTPC for identifying protein-protein interactions, we established that tcTPC allowed stringent immunoaffinity purification of the gamma-secretase complex in high salt concentrations and detergents and was compatible with mass spectrometric identification of cross-linked aph-1, presenilin-1 and nicastrin. We then applied tcTPC to identify more than 20 proteins residing in the vicinity of the cellular prion protein (PrPC), suggesting that PrP is embedded in specialized membrane regions with a subset of molecules that, like PrP, use a glycosylphosphatidylinositol anchor for membrane attachment. Many of these proteins have been implicated in cell adhesion/neuritic outgrowth, and harbor immunoglobulin C2 and fibronectin type III-like motifs.

Amino Acid Sequence↗

PubMed2004

Attenuation of neointima formation through the inhibition of DNA repair enzyme PARP-1 in balloon-injured rat carotid artery.

Increased oxidative stress is a major characteristic of restenosis after angioplasty. The oxidative stress is mainly created by oxidants such as reactive oxygen species (ROS), which are assumed to play an important role in neointima formation after angioplasty. DNA is a sensitive target for oxidants; however, oxidative DNA damage remains a poorly examined field in the pathogenesis of restenosis. In the present study, we demonstrated that the expression of the oxidative DNA damage marker 7,8-dihydro-8-oxo-2'-deoxyguanosine (8-oxo-dG) was quickly increased in rat carotid arteries after balloon injury. It reached its peak at 14 days after injury and still kept high expression at 28 days after injury. The immunostaining of 8-oxo-dG was present predominantly in the neointima. In response to oxidative DNA damage, the DNA repair enzyme poly(ADP-ribose) polymerase-1 (PARP-1) was significantly increased after balloon injury. The time course change and location of PARP-1 is similar to that of 8-oxo-dG. Daily injections of the PARP-1 inhibitor PJ34 (5 mg.kg(-1).day(-1) ip) attenuated neointima formation by approximately 40% at 7, 14, and 28 days after balloon injury. Treatment with PJ34 inhibited leukocyte infiltration and improved both anatomic (reendothelialization) and functional (endothelial function) recovery of endothelial cells after balloon injury. In conclusion, levels of oxidative DNA damage and the DNA repair enzyme PARP-1 are increased in vessels after balloon injury. Inhibition of PARP-1 attenuates neointima formation through inhibition of leukocyte infiltration and improvement of endothelial cell recovery after balloon injury. Targeting of the DNA repair enzyme might be a therapeutic strategy for restenosis.

Animals↗

PubMed2004

NMR spectroscopic analysis of neferine and isoliensinine.

Neferine and isoliensinine are the two major compositions of the Chinese medicine lotus plumule. They have extensive cardiovascular activity, such as antiarrhythmic, antithrombic and antihypertensive. In order to confirm the structures reported in the literature by explicit 1H and 13C assignments, we used a series of NMR experiments including 1H, 1H-COSY, HSQC and HMBC. The absolute configuration of neferine (C-1 and C-1') was determined as R and S and that of isoliensinine (C-1 and C-1') was determined as R and R.

Benzylisoquinolines↗

PubMed2004

Detection of DNA aneuploidy in exfoliated airway epithelia cells of sputum specimens by the automated image cytometry and its clinical value in the identification of lung cancer.

To evaluate the value of detection of DNA aneuploidy in exfoliated airway epithelia cells of sputum specimens by the automated image cytometry for the identification of lung cancer, 100 patients were divided into patient group (50 patients with lung cancer) and control group (30 patients with tuberculosis and 20 healthy people). Sputum was obtained for the quantitative analysis of DNA content of exfoliated airway epithelial cells with the automated image cytometry, together with the examinations of brush cytology and conventional sputum cytology. Our results showed that DNA aneuploidy (DI>2.5 or 5c) was found in 20 out of 50 sputum samples of lung cancer, 1 out of 30 sputum samples from tuberculosis patients, and none of 20 sputum samples from healthy people. The positive rates of conventional sputum cytology and brush cytology were 16% and 32%, which was lower than that of DNA aneuploidy detection by the automated image cytometry (P<0.01, P>0.05). Our study showed-that automated image cytometry, which uses DNA aneuploidy as a marker for tumor, can detect the malignant cells in sputum samples of lung cancer and it is a sensitive and specific method serving as a complement for the diagnosis of lung cancer.

Adult↗

PubMed2004

Total and subcellular distribution of trace elements in the liver of a mother-fetus pair of Dall's porpoises (Phocoenoides dalli).

Total and subcellular hepatic Zn, Cu, Se, Mn, V, Hg, Cd, and Ag were determined in a mother-fetus pair of Dall's porpoises (Phocoenoides dalli). Except for higher fetal Cu concentration, all maternal elements were higher. Elements existed mostly in the cytosol of both animals except in the case of maternal Ag in the microsome and fetal Cu and Ag in the nuclei and mitochondria. In the maternal cytosol, Zn, Mn, Hg, and Ag were present in the high-molecular-weight substances (HMW); Se and V were present in the low-molecular-weight substances (LMW); Cu and Cd were mostly sequestered by metallothionein (MT). In the fetal cytosol, Zn, Se, Mn, Hg, Cd, and Ag were present in the HMW and V in the LMW, while Cu and Ag were mostly associated with MT. MT isoforms were characterized using the HPLC/ICP-MS. Two and four obvious peaks appeared in the maternal and fetal MT fractions, respectively. The highest elemental ion intensities were at a retention time of 7.8 min for the mother, and for the fetus the peak elemental ion intensities occurred at a retention time of 4.3 min, suggesting that different MT isoforms may be involved in elemental accumulation in maternal and fetal hepatocytosols.

Animals↗

PubMed2004

Two-dimensional PCA: a new approach to appearance-based face representation and recognition.

In this paper, a new technique coined two-dimensional principal component analysis (2DPCA) is developed for image representation. As opposed to PCA, 2DPCA is based on 2D image matrices rather than 1D vectors so the image matrix does not need to be transformed into a vector prior to feature extraction. Instead, an image covariance matrix is constructed directly using the original image matrices, and its eigenvectors are derived for image feature extraction. To test 2DPCA and evaluate its performance, a series of experiments were performed on three face image databases: ORL, AR, and Yale face databases. The recognition rate across all trials was higher using 2DPCA than PCA. The experimental results also indicated that the extraction of image features is computationally more efficient using 2DPCA than PCA.

Algorithms↗

PubMed2004

Shear modulus of elasticity of the esophagus.

Experimental and diagnostic procedures like distension of a balloon catheter, bougie, and esophagogastroduodenoscopy can induce shear deformation in the esophageal wall. However, the shear modulus of the esophagus is yet unknown. The aim of this study was to determine the esophageal shear modulus and its dependence on the circumferential and longitudinal stresses and strains in the rat. The constitutive equation including the shear deformation based on a pseudo-strain-energy function was generated. Results were obtained using a new triaxial instrument to perform simultaneous torsion, inflation, and longitudinal stretching tests. The shear modulus varied with the inflation pressure and the longitudinal stretch ratio. The shear modulus at the longitudinal stretch ratio of 1.5 and between inflation pressures of 0 and 2.0 kPa ranged from 5.43 to 185.01 kPa. The mechanical constant of the esophagus showed that the esophageal wall was anisotropic with different stiffness in the circumferential, longitudinal, and the shear directions. The stiffness in the longitudinal direction was higher than in the circumferential direction (P < 0.001). This test can be extended for further mechanical remodeling experiments and for other tubular organs such as the small intestine or blood vessels.

Animals↗

PubMed2004

Analysis of part of the Trichophyton rubrum ESTs.

Trichophyton rubrum (T. rubrum) is the most common of the superficial fungi. In an effort to better understand the genetic and biochemical makeup of T. rubrum, we generated cDNA libraries from 3 growth stages and used these to isolate 4002 unique expressed sequence tags (ESTs). Sequence comparisons with the Genbank database allowed 1226 of the ESTs to be assigned putative functions or matched with homologs from other organisms. Of the remaining ESTs, 989 were only weakly similar to known sequences and 1787 had no identifiable functions, suggesting that they represent novel genes. We further analyzed the presence of several important genes involved in the growth, metabolism, signal transduction, pathogenesis and drug resistance in T. rubrum. This information was used to newly elucidate important metabolic pathways in T. rubrum. Taken together, our results should form the molecular basis for continued research on the physiological processes and pathogenic mechanisms of T. rubrum, and may lead to a better understanding of fungal drug resistance and identification of new drug targets.

Computational Biology↗