Search PubMed⌕ Search

Biomedical subjects

Wei Liang

Publications and source records attributed to Wei Liang.

At least 19 recordsLinked to original sources
PubMed2026

Exposure to size-specific particulate matter accelerates DNA methylation aging in people with HIV.

BACKGROUND: People with HIV (PWH) face accelerated aging and increased health risks, with DNA methylation age (DNAmAge) as a critical senescence biomarker. Particulate matter is linked to DNAmAge acceleration (DNAmAA) in general population, but its impact in PWH remains unstudied. METHODS: Thirty-two PWH from Wuhan, China, were enrolled in a prospective panel study with follow-up, and each participant underwent at least two repeated measurements during the study period. Portable air quality monitor measured PM 1 , PM 2.5 , and PM 10 exposures 72 h preblood sampling. We analyzed genome-wide DNA methylation in peripheral blood and calculated six AA metrics. Linear mixed-effects and weighted quantile sum regression models evaluated associations between particulate matter exposure and DNAmAA. RESULTS: Significant associations between particulate matter exposure and DNAmAA were observed at various lag windows. For every 10 μg/m 3 increase in 24-h average PM 2.5 , Hannum DNAmAA, Pheno DNAmAA, Grim DNAmAA, SkinBlood DNAmAA, and Elastic DNAmAA increased by 0.266 years [95% confidence interval (CI): 0.035-0.480], 0.421 years (95% CI: 0.032-0.701), 0.336 years (95% CI: 0.073-0.546), 0.295 years (95% CI: 0.021-0.495), and 0.254 years (95% CI: 0.034-0.445), respectively. PM 10 contributed most substantially to the cumulative PM effect on epigenetic AA in the lag0-24 h window. CONCLUSION: Short-term particulate matter exposure, particularly PM 10 , significantly accelerates epigenetic aging in PWH, highlighting the need to integrate air quality management into healthy aging strategies for this vulnerable population.

China↗
PubMed2006

Smad3 specific inhibitor, naringenin, decreases the expression of extracellular matrix induced by TGF-beta1 in cultured rat hepatic stellate cells.

PURPOSE: During the process of liver fibrogenesis, transforming growth factor-beta (TGF-beta) plays an essential role in modulating extracellular matrix (ECM) gene expression, and a growing body of evidence suggests that this is a Smad3-dependent process in the activated hepatic stellate cells (HSCs). Naringenin showed a significantly protective effect on experimental rat liver fibrosis, in our efforts to elucidate its antifibrosis molecular mechanisms and to find a novel target based on Smad3 signaling for challenging fibrosis diseases. METHODS: In this study, reverse transcription-polymerase chain reaction and Western blot assays were used to investigate the inhibitory effect of naringenin on ECM formation induced by TGF-beta1 in the HSC-T6 cells. RESULTS: Naringenin reduced not only the accumulation of ECM, including collagen Ialpha1 (Col Ialpha1), fibronectin (FN), and plasminogen activator inhibitor-1 (PAI-1), but also the production of Smad3 induced by TGF-beta1 in both mRNA and protein levels in a dose-dependent manner. Moreover, naringenin selectively inhibited the transcription of Smad3, but not other Smads involved in TGF-beta1 signaling pathways. CONCLUSION: Our data demonstrate that naringenin can exert antifibrogenic effects by directly or indirectly down-regulating Smad3 protein expression and phosphorylation through TGF-beta signaling.

Animals↗
PubMed2006

Effects of low-molecular-weight organic ligands and phosphate on DNA adsorption by soil colloids and minerals.

Adsorption of DNA on montmorillonite, kaolinite, goethite and soil clays from an Alfisol in the presence of citrate, tartrate and phosphate was studied. A marked decrease in DNA adsorption was observed on montmorillonite and kaolinite with increasing anion concentrations from 0 to 5 mM. However, the amount of DNA adsorbed by montmorillonite and kaolinite was enhanced when ligand concentration was higher than 5 mM. In the system of soil colloids and goethite, with the increase of anion concentrations, a steady decrease was found and the ability of ligands in depressing DNA adsorption followed the sequence: phosphate > citrate > tartrate. Compared to H2O2-treated clays (inorganic clays), a sharp decrease in DNA adsorption was observed on goethite and organo-mineral complexes (organic clays) with increasing ligand concentrations. The results suggest that the influence of anions on DNA adsorption varies with the type and concentration of anion as well as the surface properties of soil components. Introduction of DNA into the system before the addition of ligands had the greatest amount of DNA adsorption on soil colloids and goethite. Organic and inorganic ligands promoted DNA adsorption on montmorillonite and kaolinite when ligands were introduced into the system before the addition of DNA. The results obtained in this study have important implications for the understanding of the persistence and fate of DNA in soil environments especially rhizosphere soil where various organic and inorganic ligands are active.

Adsorption↗
PubMed2006

Microcalorimetric studies on the adsorption of DNA by soil colloidal particles.

This study applied TAM air isothermal calorimeter to measure the adsorption enthalpies of DNA on eight colloidal fractions from permanent-charge and variable-charge soils. The adsorption of DNA on soil colloids was also examined by equilibrium adsorption analysis. The data evaluated from isotherms fitted by Langmuirean model revealed that the affinity of DNA for variable-charge soil colloids was higher than that for permanent-charge soil colloids. More tightly bound DNA molecules were observed on coarse clays and inorganic clays than on fine clays and organic clays, respectively. The adsorption enthalpies of DNA on permanent-charge soil colloids were higher than those on variable-charge soil colloids. DNA adsorption on organic clays is endothermic, whereas that on inorganic clays is exothermic. Dehydration and electrostatic repulsion were considered to cause the higher adsorption enthalpies of DNA with organic clays, while hydrogen bonding, ligand exchange and electrostatic attraction result in the lower DNA adsorption enthalpies on inorganic clays. The thermodynamic parameters presented in this study have important implication for providing further insight into mechanisms of the adsorption of DNA on soil particles.

Adsorption↗
PubMed2006

Mannose selection system used for cucumber transformation.

The selectable marker system, which utilizes the pmi gene encoding for phosphomannose-isomerase that converts mannose-6-phosphate to fructose-6-phosphate, was adapted for Agrobacterium-mediated transformation of cucumber (Cucumis sativus L.). Only transformed cells were capable of utilizing mannose as a carbon source. The highest transformation frequency of 23% was obtained with 10 g/l mannose and 10 g/l sucrose in the medium. Molecular, genetic analysis, and PMI activity assay showed that the regenerated shoots contained the pmi gene and the gene was transmitted to the progeny in a Mendelian fashion. The results indicated that the mannose selection system, which is devoid of the disadvantages of antibiotic or herbicide selection, could be used for cucumber Agrobacterium-mediated transformation.

Cucumis sativus↗
PubMed2006

siRNA-containing liposomes modified with polyarginine effectively silence the targeted gene.

Development of RNA interference (RNAi) technology utilizing the short interfering RNA sequences (siRNA) based 'targeted' therapeutics has focused on creating methods for delivering siRNAs to cells and for enhancing siRNA stability in vitro and in vivo. Here, we describe a novel approach for siRNA cellular delivery using siRNA encapsulated into liposomes additionally bearing arginine octamer (R8) molecules attached to their outer surface (R8-liposomes). The R8-liposomal human double minute gene 2 (HDM2)-siRNA demonstrated a significant stability against degradation in the blood serum (siRNA-loaded R8-liposomes remained intact even after 24-h incubation), and higher transfection efficiency into all three tested lung tumor cell lines. siRNA delivery successfully proceeds in the presence of plasma proteins, and R8-liposomes demonstrate low non-specific toxicity. The mechanism of action of R8-liposome-encapsulated siRNA is associated with the RNAi-mediated degradation of the target mRNA. siRNA in R8-liposomes effectively inhibited the targeted gene and significantly reduced the proliferation of cancer cells. The approach offers the potential for siRNA delivery for various in vitro and in vivo applications.

Cell Line, Tumor↗
PubMed2006

Transmission characteristics of a Fabry-Perot etalon-microtoroid resonator coupled system.

The transmission spectra of a Fabry-Perot etalon coupled to a microtoroid resonator are studied theoretically and experimentally. The resonance line shapes depend strongly on the resonance wavelength detuning and coupling strength between the two resonators. A wide variety of line shapes, ranging from a single to triple peaks, symmetric to asymmetric Fano-like peaks, and notches were predicted and observed experimentally. The capability to modify the spectral line shapes by tuning the coupling between or losses of two resonators may find applications in optical filtering, switching, sensing, and dispersion engineering.

Journal Article↗
PubMed2006

TM4 microarray software suite.

Powerful specialized software is essential for managing, quantifying, and ultimately deriving scientific insight from results of a microarray experiment. We have developed a suite of software applications, known as TM4, to support such gene expression studies. The suite consists of open-source tools for data management and reporting, image analysis, normalization and pipeline control, and data mining and visualization. An integrated MIAME-compliant MySQL database is included. This chapter describes each component of the suite and includes a sample analysis walk-through.

Algorithms↗
PubMed2006

von Hippel-Lindau gene mutation in non-syndromic familial pheochromocytomas.

Approximately 50% of patients with non-syndromic familial pheochromocytomas had germline von Hippel-Lindau (VHL) gene mutations, but no reports on the subject were available in China. A total of five unrelated Chinese families with non-syndromic familial pheochromocytomas were screened for VHL gene mutation by polymerase chain reaction (PCR) and subsequent direct sequencing. Missense germline mutations of VHL gene were detected in four of the five families. Arg161Gln (695G-A) mutation was found in two families, and the other two families had Leu163Phe (700C-T) and Arg167Trp (712C-T) mutation, respectively. In conclusion, VHL gene may have frequent mutation in Chinese patients with non-syndromic familial pheochromocytomas.

Adrenal Gland Neoplasms↗
PubMed2006

[Cell penetrating peptides enhance intracellular translocation and function of siRNA encapsulated in Pegylated liposomes].

AIM: To prepare the PEGylated liposomes modified with cell penetrating peptides, which protect siRNA from nuclease degradation and deliver efficiently siRNA into cells to facilitate silencing of target gene. METHODS: The purity of R8-PEG-PE and pNP-PEG-PE was detected by HPLC; the quantity of R8, PEG-DPPE modified R8, and R8 attached to the out membrane surface of the liposomal siRNA by transfer from R8-PEG-DPPE micelles to the liposomes was tested by fluorescence; Size and size distribution of siRNA loaded liposomes with and without attached R8 were determined by Zetasizer 5000; A comparison of mediated siRNA transfection efficiency between R8-liposomes and lipofectamine 2000 was examined by individual inside cell fluorescence intensity; The growth inhibition of small cell lung carcinoma NCI-H446 cells treated with R8-liposomal hdm2-siRNA or lipofectamine 2000-hdm2-siRNA complex was tested by MTT assay. RESULTS: The retention times of PEG-DPPE and R8-PEG-DPPE were 9.0 min and 7.8 min, respectively. Fluorescence scanning indicated that lipids composed of liposomes and siRNAs didn't interfere to the determination of R8 when it was attached to the liposomal siRNA. The cells treated with R8-liposomal hdm2-siRNA significantly enhanced the cellular uptake of hdm2-siRNA and facilitated the functions of hdm2-siRNA through silencing of target gene which, in turn, inhibited tumor cell growth, compared with lipofectamine 2000. CONCLUSION: The R8 attached liposomes are shown to be powerful carriers for delivery siRNAs into cell to silence targeted gene.

Carcinoma, Small Cell↗
PubMed2005

Adsorption, desorption and activities of acid phosphatase on various colloidal particles from an Ultisol.

Adsorption, desorption and activity of acid phosphatase on various soil colloidal particles and pure clay minerals were studied. Higher adsorption amounts and low percentage of desorption of acid phosphatase were found on fine soil clays (<0.2 microm). Electrostatic force and ligand exchange are the major driving forces that are involved in the adsorption of enzymes on soil clays. More enzyme molecules were adsorbed on soil clays in the presence of organic components. However, enzymes on organic clays were more easily released. One-third of the enzyme on goethite was adsorbed via ligand exchange process. Some other interactions, such as van der Waals force, hydrophobic force and hydrogen bonding may be more important in the adsorption of enzyme on kaolinite and the enzyme in this system cannot be easily removed. Coarse clays (0.2-2 microm) and inorganic soil clays had higher affinities for enzyme molecules than fine clays and organic clays, respectively. The activity of enzyme bound on soil clays was inhibited and the thermal stability was increased in the presence of organic matter. Data obtained in this study are helpful for a better understanding of the interactions of enzymes with inorganic and organic constituents in soil and associated environments.

Acid Phosphatase↗
PubMed2005

B-cell delivered gene transfer of human S-Ag-Ig fusion protein protects from experimental autoimmune uveitis.

Uveitis is an important autoimmune disease affecting an estimated 2.3 million Americans. This disease is manifested by inflammation of the retina mediated by the infiltration of T lymphocytes that recognize "S-Antigen" (S-Ag). Current therapies involve the life-long use of immunosuppressive drugs, including steroids. The ability to induce specific tolerance to S-Ag would be desirable and allow patients to be weaned off of steroid therapy. In this study, we determined that S-Ag-Ig retroviral vector was capable of preventing EAU (experimental autoimmune uveoretinitis) in Lewis rats induced by immunization with bovine S-Ag (BoS-Ag). Importantly, B-cell delivered gene therapy with S-Ag-Ig can ameliorate ongoing EAU when the treatment was initiated after rats had been immunized. Furthermore, we have successfully induced tolerance in HLA-DR3 transgenic mice with respect to the T-cell proliferative response. These results demonstrate proof of principle for future efforts to develop this approach for clinical application in patients with uveoretinitis.

Animals↗
PubMed2005

Localization and potential function of androgen receptor in rat salivary gland.

AIM: To investigate the localization and quantity of androgen receptor (AR) in the salivary glands of rats with further analysis on the effect of castration. METHODS: Sixty male Wistar rats, aged 30-60 days, were randomly divided into three groups (castrated, sham-operated and normal controls) with 20 rats in each group. The rats in the castrated group were castrated and the submaxillary glands were removed after 1 week. The salivary glands of the rats in the sham-operated and the normal control groups were also removed. Parts of the salivary glands were fixed for immunohistochemistry and in situ hybridization assays. Other parts were used for Western blot. RESULTS: AR immunoreactivity in the three groups was localized in the glandular epithelial cells of the serous acinus and the glandular duct of the salivary gland, mainly in the nuclei. AR mRNA hybridization signals in the salivary glands of the castrated group were mainly distributed in the epithelial cells of the convoluted and secretary ducts; AR mRNA in the sham-operated and the normal control groups were found in the epithelial cells of the convoluted, the secretary and the excretory ducts. The quantity of AR in the salivary glands was decreased significantly in the castrated rats compared with the sham-operated and the normal controls. Moreover, epidermal growth factor (EGF) secreted by the salivary glands was also decreased in the castrated rats. CONCLUSION: Castration appears to affect the production of AR in the salivary gland and the distribution of the AR mRNA and could further affect the function of the salivary gland. The changes of AR and the distribution of AR mRNA may play an important role in the interactions between the testes and the salivary gland.

Animals↗
PubMed2005

[Relationship between different renal functional state with therapeutic effect on diabetic foot ulcers].

OBJECTIVE: To study the relationship between renal functional state and the therapeutic effect and prognosis of foot ulcers in the patients with diabetic mellitus. METHODS: The renal function was evaluated in term of glomerular filtration rate, microalbuminuria, proteinuria, blood urea nitrogen (BUN) and creatinine (Cr) levels in 126 patients with I-V class diabetic foot ulcers (according to Wagner classic standard) before the treatment, and then these patients were divided into 1-5 classes (according to Mogenson standard) and given systemic treatment and local debridement, with astragalus for topical application. The time of growth of granulation tissue (GT), the time of healing (HT), the amputation rate and mortality were observed. RESULTS: GT and HT of ulcer prolonged with worsening of diabetic nephropathy regardless of the disease phase of foot ulcers, especially the GT and HT of foot ulcers were significantly longer in IV and V phases of diabetic nephropathy than those of III phase diabetic nephropathy though the conditions of their foot ulcers were about the same. GT and HT in all the patients with the foot ulcers in the similar condition exhibited significantly positive linear correlation with the severity of diabetic nephropathy (r(1)=2.344 and r(2)=2.563, respectively, both P<0.05). The mortality of I-III phase diabetic nephropathy was significantly lower than that of IV and V phase diabetic nephropathy when the foot ulcers of these patients were of the same extent (P<0.05). CONCLUSION: A worsening of renal function would affect the treatment effect and prognosis of foot ulcers in the patients with diabetic foot ulcers, implicating that it is very important to improve the renal function in the treatment of patients with diabetic foot ulcers.

Combined Modality Therapy↗
PubMed2004

Expression of vascular endothelial growth factor-C and the relationship between lymphangiogenesis and lymphatic metastasis in colorectal cancer.

AIM: To investigate the expression of vascular endothelial growth factor-C (VEGF-C) and the relationship between VEGF-C and lymphangiogenesis, lymph node metastasis in colorectal cancer. METHODS: Fifty six cases of colorectal cancer were selected randomly. Expression of VEGF-C was detected by immunohistochemistry, and lymphatic vessels were stained by enzyme histochemical method. RESULTS: VEGF-C expression was found in 66.7% (37/56) patients. In VEGF-C positive and negative patients, the lymphatic vessel density was 25.16+/-7.52 and 17.14+/-7.22, respectively (P<0.05). The rate of lymph node metastasis in VEGF-C positive patients (81.1%) was significantly higher than that in the negative group (42.1%). CONCLUSION: VEGF-C expression may induce lymphangiogenesis in colorectal cancer, as a result, tumor cells can entry the lymphatic vessels easily. VEGF-C may serve as a useful prognotic factor in colorectal carcinoma.

Adult↗
PubMed2004

Resistance of the human beta1-adrenergic receptor to agonist-induced ubiquitination: a mechanism for impaired receptor degradation.

Down-regulation is a classic response of most G protein-coupled receptors to prolonged agonist stimulation. We recently showed that when expressed in baby hamster kidney cells, the human beta1-but not the beta2-adrenergic receptor (AR) is totally resistant to agonist-mediated down-regulation, whereas both have similar rates of basal degradation (Liang, W., Austin, S., Hoang, Q., and Fishman, P. H. (2003) J. Biol. Chem. 278, 39773-39781). To identify the underlying mechanism(s) for this resistance, we investigated the role of proteasomes, lysosomes, and ubiquitination in the degradation of beta1AR expressed in baby hamster kidney and human embryonic kidney 293 cells. Both lysosomal and proteasomal inhibitors reduced beta1AR degradation in agonist-stimulated cells but were less effective on basal degradation. To determine whether beta1AR trafficked to lysosomes we used confocal fluorescence microscopy. We observed some colocalization of beta1AR and lysosomal markers in agonist-treated cells but much less than that of beta2AR even in cells co-transfected with arrestin-2, which increases beta1AR internalization. Ubiquitination of beta2AR readily occurred in agonist-stimulated cells, whereas ubiquitination of beta1AR was not detectable even under conditions optimal for that of beta2AR. Moreover, in cells expressing betaAR chimeras in which the C termini have been switched, the chimeric beta1AR with beta2AR C-tail underwent ubiquitination and down-regulation, but the chimeric beta2AR with beta1AR C-tail did not. Our results demonstrate for the first time that beta1AR and beta2AR differ in the ability to be ubiquitinated. Because ubiquitin serves as a signal for sorting membrane receptors to lysosomes, the lack of agonist-mediated ubiquitination of beta1AR may prevent its extensive trafficking to lysosomes and, thus, account for its resistance to down-regulation.

Acetylcysteine↗
PubMed2004

Modal analysis of Bragg onion resonators.

From analysis of the high Q modes in a Bragg onion resonator with an omnidirectional reflector cladding, we establish a close analogy between such a resonator and a spherical hollow cavity in perfect metal. We demonstrate that onion resonators are ideal for applications that require a large spontaneous-emission factor beta, such as thresholdless lasers and single-photon devices.

Journal Article↗