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Biomedical subjects

Chun Yang

Publications and source records attributed to Chun Yang.

At least 19 recordsLinked to original sources
PubMed2025

Steroid hormones in pain: Mechanistic underpinnings and therapeutic perspectives.

Pain is a complex sensory and emotional experience that severely affects an individual's quality of life and health status. Steroid hormones, as important regulatory substances in the human body, are extensively involved in various physiological and pathological processes. In recent years, remarkable progress has been made in the research of steroid hormones in the field of pain. They play a crucial role in the occurrence, development, and treatment of pain. This review comprehensively elaborates on the roles and therapeutic mechanisms of steroid hormones in pain, explores the performances of glucocorticoids, mineralocorticoids, sex hormones, etc. in different pain models, as well as the molecular mechanisms by which they regulate pain through genomic and non-genomic effects, aiming to provide a theoretical basis for the clinical treatment of pain.

Humans↗
PubMed2025

Genetic targets related to aging for the treatment of coronary artery disease.

BACKGROUND: Coronary Artery Disease (CAD) is the most common cardiovascular disease worldwide, threatening human health, quality of life and longevity. Aging is a dominant risk factor for CAD. This study aims to investigate the potential mechanisms of aging-related genes and CAD, and to make molecular drug predictions that will contribute to the diagnosis and treatment. METHODS: We downloaded the gene expression profile of circulating leukocytes in CAD patients (GSE12288) from Gene Expression Omnibus database, obtained differentially expressed aging genes through "limma" package and GenaCards database, and tested their biological functions. Further screening of aging related characteristic genes (ARCGs) using least absolute shrinkage and selection operator and random forest, generating nomogram charts and ROC curves for evaluating diagnostic efficacy. Immune cells were estimated by ssGSEA, and then combine ARCGs with immune cells and clinical indicators based on Pearson correlation analysis. Unsupervised cluster analysis was used to construct molecular clusters based on ARCGs and to assess functional characteristics between clusters. The DSigDB database was employed to explore the potential targeted drugs of ARCGs, and the molecular docking was carried out through Autodock Vina. Finally, single-cell data (GSE159677) of arterial intima was used to further explore the expression of aging signature genes in different cell subpopulations. RESULTS: We identified 8 ARCGs associated with CAD, in which HIF1A and FGFR3 were up while NOX4, TCF7L2, HK3, CDK18, TFAP4, and ITPK1 were down in CAD patients. Based on this, CAD patients can be divided into two molecular clusters, among which cluster A mainly involves functional pathways such as ECM receptor interaction and focal adhesion; cluster B mainly involves functional pathways such as amimo sugar and nucleotide sugar metabolism and pyrimidine metabolism. In addition, the molecular docking results showed that retinoic acid and resveratrol had good binding affinity with targets genes. Further single-cell analysis results showed that NOX4, TCF7L2, ITPK1, and HIF1A were specifically expressed in different types of cells in atherosclerotic tissues. CONCLUSION: Our study identified several ARCGs that may be involved in the pathogenesis and progression of CAD. Further, retinoic acid and resveratrol were potential candidate molecule drugs for inhibiting these targets.

Humans↗
PubMed2006

Identification, characterization and quantitation of pyrogenic polycylic aromatic hydrocarbons and other organic compounds in tire fire products.

On 15 August 2001, a tire fire took place at the Pneu Lavoie Facility in Gatineau, Quebec, in which 4000 to 6000 new and recycled tires were stored along with other potentially hazardous materials. Comprehensive gas chromatography-mass spectrometry (GC-MS) analyses were performed on the tire fire samples to facilitate detailed chemical composition characterization of toxic polycyclic aromatic hydrocarbons (PAHs) and other organic compounds in samples. It is found that significant amounts of PAHs, particularly the high-ring-number PAHs, were generated during the fire. In total, 165 PAH compounds including 13 isomers of molecular weight (MW) 302, 10 isomers of MW 278, 10 isomers of MW 276, 7 isomers of MW 252, 7 isomers of MW 228, and 8 isomers of MW 216 PAHs were positively identified in the tire fire wipe samples for the first time. Numerous S-, O-, and N-containing PAH compounds were also detected. The identification and characterization of the PAH isomers was mainly based on: (1) a positive match of mass spectral data of the PAH isomers with the NIST authentic mass spectra database; (2) a positive match of the GC retention indices (I) of PAHs with authentic standards and with those reported in the literature; (3) agreement of the PAH elution order with the NIST (US National Institute of Standards and Technology) Standard Reference Material 1597 for complex mixture of PAHs from coal tar; (4) a positive match of the distribution patterns of PAH isomers in the SIM mode between the tire fire samples and the NIST Standard Reference Materials and well-characterized reference oils. Quantitation of target PAHs was done on the GC-MS in the selected ion monitoring (SIM) mode using the internal standard method. The relative response factors (RRF) for target PAHs were obtained from analyses of authentic PAH standard compounds. Alkylated PAH homologues were quantitated using straight baseline integration of each level of alkylation.

Automobiles↗
PubMed2006

Forensic fingerprinting of diamondoids for correlation and differentiation of spilled oil and petroleum products.

Diamondoids (adamantanes and diamantanes) are rigid, three-dimensionallyfused cyclohexyl-ring alkane compounds that can be found in almost all crude oils and in most petroleum products. Forforensic environmental investigations, the most commonly used biomarkers are high molecular weight (MW) tri- to pentacyclic terpanes and steranes. Most of these high MW biomarkers, however, are removed from the original crude oil feedstocks during the refining processes, while smaller biomarkers including diamondoids are concentrated in petroleum products. Fingerprinting diamondoids could thus provide another diagnostic means for correlation and differentiation of spilled oils and be particularly valuable for light to midrange distillates, such as jet and diesel fuels, the source of which may be difficult to identify using routine biomarker techniques. In this work, a reliable GC-MS analytical method has been developed for characterization and quantitation of diamondoids. The method detection limits for five target diamondoids were determined to be in the range of 0.06-0.14 microg/g oil. Distributions of diamondoids in over 100 different oils and refined products were quantitatively compared. The concentrations of four groups of target biomarkers were found, in general, to decrease in the order of sesquiterpanes > terpanes and steranes > adamantanes > diamantanes in both crude oils and refined products. A number of indices of admantanes and diamantanes have been developed and assessed as source indicators using their diagnostic powers (DP). The effects of evaporative weathering and biodegradation on alteration of diamondoid distributions have been quantitatively investigated. Finally, a spill case study by statistical evaluation of diagnostic ratios using the "two-tailed" Student's tapproach is presented to illustrate the unique utility of diamondoids for correlation and differentiation of unknown spilled diesels.

Adamantane↗
PubMed2006

Recombinant M. smegmatis vaccine targeted delivering IL-12/GLS into macrophages can induce specific cellular immunity against M. tuberculosis in BALB/c mice.

In the present study, we constructed a viable therapeutic vaccine of recombinant M. smegmatis mediated IL-12/GLS (granulysin) gene transfer into murine macrophages to exert the immunotherapy effects on the Mycobacterium tuberculosis infection. We tested this recombinant therapeutic vaccine in an in vivo study to determine its capability of stimulating host specific immune responses against M. tuberculosis. BALB/c mice intranasally immunized with the therapeutic vaccine developed an efficient Th1 protective immune response against M. tuberculosis which was equal to that of the BCG strain. Inoculation intranasally with this viable vaccine induced high level of serum IFN-gamma, IL-12 and IgG2a. The viable vaccine was capable of inducing purified protein derivative (PPD) antigen-specific splenocytes proliferation and IFN-gamma production from T cells in spleens of the immunized mice. In addition, intranasally inoculation with the viable vaccine can induce PPD antigen-specific sIgA production in the broncho-alveolar lavage fluid (BALF) of the immunized mice. No change of IL-4 level was found in all groups. The therapeutic mechanism of this viable vaccine against M. tuberculosis infection observed here appeared to be a result of the specific Th1 immune response activated by mycobacterium antigen from M. smegmatis and the expression of sIL-12/GLS in alveolar macrophages via the M. smegmatis-mediated gene transfer method. This research demonstrates that the therapeutic gene can be introduced into a host by viable mycobacteria works to induce the host specific immune response against M. tuberculosis infection in vivo. Since this therapeutic vaccine can strongly induce specific Th1 responses against M. tuberculosis in BALB/c mice and has no obviously harmfulness to the host simultaneously, the recombinant vaccine might be a potential candidate therapeutic vaccine against tuberculosis.

Animals↗
PubMed2006

Effects of GM-CSF on the stem cells mobilization and plasma C-reactive protein levels in patients with acute myocardial infarction.

BACKGROUND: Stem cell mobilization with granulocyte colony-stimulating factor (G-CSF) has been proposed to improve cardiac function and prevent ventricular remodeling after acute myocardial infarction (AMI) in preclinical and clinical studies. It has been demonstrated that granulocyte-macrophage colony-stimulating factor (GM-CSF) can improve collateral flow in patients with coronary artery disease. In this study, we used GM-CSF to mobilize the bone marrow stem cells (BMSCs) in patients with AMI and assessed the safety, feasibility and efficacy of this treatment. METHODS: Twenty patients with AMI were randomly divided into GM-CSF group (10 microg/kg body weight, for 7 days) and control group (saline). The absolute counts of CD34 positive cells in peripheral blood were enumerated with flow cytometry. Plasma levels of C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrotic factor-alpha (TNF-alpha) were measured on days 1, 3, 7, 10 and 14. Echocardiography (UCG) was done on day 7 and after 12 months. RESULTS: Peripheral CD34 positive cells in GM-CSF patients obviously increased shortly after using GM-CSF and peaked on day 7 (p<0.01 versus controls). GM-CSF group had significantly higher mean level of plasma CRP than controls on day 10 (p<0.05). The levels of IL-6 and TNF-alpha in therapy patients were as same as in controls. Left ventricular ejection fraction (EF) at 12 months was significantly greater than that on day 7 in GM-CSF patients (p<0.05). The EF in controls had no obvious differences in follow-up. There were no statistically differences regarding the left ventricular end-systolic volume (LVESV), the left ventricular end-diastolic volume (LVEDV) and the resting wall thickening (WT) in the infarct zone in two groups in follow-up. CONCLUSIONS: Our results demonstrate that GM-CSF can effectively mobilize the CD34 positive cells and at the same time may increase the levels of plasma CRP in patients with AMI. The remote effects of this drug need to be further defined.

Aged↗
PubMed2006

Adenoviral-mediated modulation of Sim1 expression in the paraventricular nucleus affects food intake.

Haploinsufficency of Sim1, which codes for a basic helix-loop-helix-PAS (PER-ARNT-SIM) transcription factor, causes hyperphagia in mice and humans, without decrease in energy expenditure. Sim1 is expressed in several areas of the brain, including the developing and postnatal paraventricular nucleus (PVN), a region of the hypothalamus that controls food intake. We have previously found that the number of PVN cells is decreased in Sim1+/- mice, suggesting that their hyperphagia is caused by a developmental mechanism. However, the possibility that Sim1 functions in the postnatal PVN to control food intake cannot be ruled out. To explore this hypothesis, we used adenoviral vectors to modulate Sim1 expression in the postnatal PVN of wild-type mice. Unilateral stereotaxic injection into the PVN of an adenoviral vector producing a short hairpin RNA directed against Sim1 resulted in a significant increase in food intake, which peaked to 22% 6 d after the procedure, compared with the injection of a control virus. In contrast, injection of an adenovirus that expresses Sim1 induced a decrease in food intake that was maximal on the seventh day after the procedure, reaching 20%. The impact of bilateral injections of these vectors into the PVN was not greater than that of unilateral injections. Together, these results strongly suggest that Sim1 functions along a physiological pathway to control food intake.

Adenoviridae↗
PubMed2006

Improved endcapping method of monolithic silica columns.

Following a bonding reaction with octadecyldimethyl-N,N-diethylaminosilane (ODS-DEA), a monolithic silica was subjected to consequential on-line endcapping reactions with hexamethyldisilazane (HMDS) or N-(trimethylsilyl)imidazole (TMSI) to compare the two reagents. Endcapping of monolithic silica C(18) columns prepared by a manufacturer was also studied. After endcapping with TMSI in acetonitrile (ACN), all columns provided better performance for hydrogen-bonding compounds and basic compounds than C(18) phases endcapped with HMDS. TMSI endcapping of commercial Chromolith Performance columns also gave improved performance. The results indicate that one can significantly improve the performance of monolithic silica C(18) columns for basic compounds by a simple on-column reaction with TMSI in ACN at a relative low temperature.

Amphetamine↗
PubMed2006

Simultaneous determination of endocrine-disrupting phenols and steroid estrogens in sediment by gas chromatography-mass spectrometry.

A simple and effective method has been developed to simultaneously determine endocrine-disrupting phenolic xenoestrogens and steroid estrogens in sediment by using ultra-sonicated extraction in combination with silica gel fractionation, derivatization with pentafluropropionic anhydride, and gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring mode (SIM). Satisfactory recoveries have been obtained for phenolic xenoestrogens and steroid estrogens. The method enables the determination of targets at concentrations of lower nanogram-per-gram in sediments. The method has been successfully applied to the sediments collected from Pearl River Estuary (PRE), South China Sea, China. Nonylphenol and bisphenol-A (BPA) were detected in the range from 204.2 to 664.5 ng/g and 0.6 to 4.0 ng/g, respectively. None of the estrogens were found in the sediment samples.

Benzhydryl Compounds↗
PubMed2006

Convergence of Itch-induced ubiquitination with MEKK1-JNK signaling in Th2 tolerance and airway inflammation.

The immune system is capable of mounting robust responses against invading pathogens but refrains from attacking self. Many studies have focused on tolerance induction of Th1 cells, whose failure results in development of autoimmune diseases. However, the molecular mechanisms governing tolerance induction in Th2 cells and its relation to allergic responses remain unclear. Here we used both in vivo and in vitro protocols to demonstrate that Th2 cells either containing a mitogen and extracellular kinase kinase 1 (MEKK1) mutant or lacking JNK1 or the E3 ubiquitin ligase Itch cannot be tolerized. In a mouse allergic model, injection of high-dose tolerizing antigen failed to block the development of airway inflammation in Itch-/- mice. This study suggests that MEKK1-JNK signaling regulates Itch E3 ligase-mediated tolerogenic process in Th2 cells. These findings have therapeutic implications for allergic diseases.

Animals↗
PubMed2006

Radial spoke proteins of Chlamydomonas flagella.

The radial spoke is a ubiquitous component of '9+2' cilia and flagella, and plays an essential role in the control of dynein arm activity by relaying signals from the central pair of microtubules to the arms. The Chlamydomonas reinhardtii radial spoke contains at least 23 proteins, only 8 of which have been characterized at the molecular level. Here, we use mass spectrometry to identify 10 additional radial spoke proteins. Many of the newly identified proteins in the spoke stalk are predicted to contain domains associated with signal transduction, including Ca2+-, AKAP- and nucleotide-binding domains. This suggests that the spoke stalk is both a scaffold for signaling molecules and itself a transducer of signals. Moreover, in addition to the recently described HSP40 family member, a second spoke stalk protein is predicted to be a molecular chaperone, implying that there is a sophisticated mechanism for the assembly of this large complex. Among the 18 spoke proteins identified to date, at least 12 have apparent homologs in humans, indicating that the radial spoke has been conserved throughout evolution. The human genes encoding these proteins are candidates for causing primary ciliary dyskinesia, a severe inherited disease involving missing or defective axonemal structures, including the radial spokes.

Amino Acid Sequence↗
PubMed2006

Visualizing the transient electroosmotic flow and measuring the zeta potential of microchannels with a micro-PIV technique.

We have demonstrated a transient micro particle image velocimetry (micro-PIV) technique to measure the temporal development of electroosmotic flow in microchannels. Synchronization of different trigger signals for the laser, the CCD camera, and the high-voltage switch makes this measurement possible with a conventional micro-PIV setup. Using the transient micro-PIV technique, we have further proposed a method on the basis of inertial decoupling between the particle electrophoretic motion and the fluid electroosmotic flow to determine the electrophoretic component in the particle velocity and the zeta potential of the channel wall. It is shown that using the measured zeta potentials, the theoretical predictions agree well with the transient response of the electroosmotic velocities measured in this work.

Chemistry, Physical↗
PubMed2006

Negative regulation of the E3 ubiquitin ligase itch via Fyn-mediated tyrosine phosphorylation.

Conjugation of ubiquitin (Ub) to a protein substrate targets the substrate for degradation or functional modification, which is tightly controlled by diverse mechanisms including phosphorylation of the substrate. An emerging mechanism involves regulation of the E3 Ub ligase, for example, the JNK-dependent phosphorylation and activation of Itch E3 ligase, which controls the turnover of Jun proteins and T cell differentiation. Here we show that Itch is also modulated by an Src kinase Fyn via tyrosine phosphorylation at the Tyr371 residue. Fyn associates with Itch, and loss of Fyn results in reduced Itch phosphorylation. Importantly, tyrosine phosphorylation of Itch appears to reduce its interaction with its substrate JunB. The turnover of JunB is accelerated in Fyn-deficient T cells, which is further reconstituted by Itch Tyr371 mutation. Thus, in contrast to the activation pathway mediated by serine/threonine phosphorylation, tyrosine phosphorylation of Itch plays a negative role in modulating Itch-promoted ubiquitination.

Amino Acid Sequence↗
PubMed2006

Assessment of Joule heating and its effects on electroosmotic flow and electrophoretic transport of solutes in microfluidic channels.

Joule heating is inevitable when an electric field is applied across a conducting medium. It would impose limitations on the performance of electrokinetic microfluidic devices. This article presents a 3-D mathematical model for Joule heating and its effects on the EOF and electrophoretic transport of solutes in microfluidic channels. The governing equations were numerically solved using the finite-volume method. Experiments were carried out to investigate the Joule heating associated phenomena and to verify the numerical models. A rhodamine B-based thermometry technique was employed to measure the solution temperature distributions in microfluidic channels. The microparticle image velocimetry technique was used to measure the velocity profiles of EOF under the influence of Joule heating. The numerical solutions were compared with experimental results, and reasonable agreement was found. It is found that with the presence of Joule heating, the EOF velocity deviates from its normal "plug-like" profile. The numerical simulations show that Joule heating not only accelerates the sample transport but also distorts the shape of the sample band.

Electrophoresis↗
PubMed2006

A method for simultaneously determining the zeta potentials of the channel surface and the tracer particles using microparticle image velocimetry technique.

The zeta potentials of channel surfaces and tracer particles are of importance to the design of electrokinetic microfluidic devices, the characterization of channel materials, and the quantification of the microparticle image velocimetry (microPIV) measurement of EOFs. A method is proposed to simultaneously measure the zeta potentials of the channel surface and the tracer particles in aqueous solutions using the microPIV technique. Through the measurement of the steady velocity distributions of the tracer particles in both open- and closed-end rectangular microchannels under the same water chemistry condition, the electrophoretic velocity of the tracer particles and the EOF field of the microchannel are determined using the expressions derived in this study for the velocity distributions of charged tracer particles in the open- and closed-end rectangular microchannels. Thus, the zeta potentials of the tracer particles and the channel surfaces are simultaneously obtained using the least-square method to fit the microPIV measured velocity distribution of the tracer particles. Measurements were carried out with a microPIV system to determine the zeta potentials of the channel wall and the fluorescent tracer particles in deionized water and sodium chloride and boric acid solutions of various concentrations.

Electrophoresis↗
PubMed2006

Adrenal insufficiency in patients with cirrhosis, severe sepsis and septic shock.

Patients with cirrhosis are susceptible to bacterial infection, which can result in circulatory dysfunction, renal failure, hepatic encephalopathy, and a decreased survival rate. Severe sepsis is frequently associated with adrenal insufficiency, which may lead to hemodynamic instability and a poor prognosis. We evaluated adrenal function using short corticotropin stimulation test (SST) in 101 critically ill patients with cirrhosis and severe sepsis. Adrenal insufficiency occurred in 51.48% of patients. The patients with adrenal insufficiency had a higher hospital mortality rate when compared with those with normal adrenal function (80.76% vs. 36.7%, P < .001). The cumulative rates of survival at 90 days were 15.3% and 63.2% for the adrenal insufficiency and normal adrenal function groups, respectively (P < .0001). The hospital survivors had a higher cortisol response to corticotropin (16.2 +/- 8.0 vs. 8.5 +/- 5.9 microg/dL, P < .001). The cortisol response to corticotropin was inversely correlated with various disease severity, Model for End-Stage Liver Disease, and Child-Pugh scores. Acute physiology, age, chronic health evaluation III score, and cortisol increment were independent factors to predict hospital mortality. Mean arterial pressure on the day of SST was lower in patients with adrenal insufficiency (60 +/- 14 vs. 74.5 +/- 13 mm Hg, P < .001), and a higher proportion of these patients required vasopressors (73% vs. 24.48%, P < .001). Mean arterial pressure, serum bilirubin, vasopressor dependency, and bacteremia were independent factors that predicted adrenal insufficiency. In conclusion, adrenal insufficiency is common in critically ill patients with cirrhosis and severe sepsis. It is related to functional liver reserve and disease severity and is associated with hemodynamic instability, renal dysfunction, and increased mortality.

Adrenal Glands↗
PubMed2006

Rapid protein identification using monolithic enzymatic microreactor and LC-ESI-MS/MS.

A monolithic enzymatic microreactor was prepared in a fused-silica capillary by in situ polymerization of acrylamide, glycidyl methacrylate (GMA) and ethylene dimethacrylate (EDMA) in the presence of a binary porogenic mixture of dodecanol and cyclohexanol, followed by ammonia solution treatment, glutaraldehyde activation and trypsin modification. The choice of acrylamide as co-monomer was found useful to improve the efficiency of trypsin modification, thus, to increase the enzyme activity. The optimized microreactor offered very low back pressure, enabling the fast digestion of proteins flowing through the reactor. The performance of the monolithic microreactor was demonstrated with the digestion of cytochrome c at high flow rate. The digests were then characterized by CE and HPLC-MS/MS with the sequence coverage of 57.7%. The digestion efficiency was found over 230 times as high as that of the conventional method. In addition, for the first time, protein digestion carried out in a mixture of water and ACN was compared with the conventional aqueous reaction using MS/MS detection, and the former solution was found more compatible and more efficient for protein digestion.

Animals↗