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Biomedical subjects

Y Cui

Publications and source records attributed to Y Cui.

At least 55 records · Page 3Linked to original sources
PubMed2001

Cryoglobulinemic glomerulonephritis in thymic stromal lymphopoietin transgenic mice.

Mixed cryoglobulins are complexes of immunoglobulins that reversibly precipitate in the cold and lead to a systemic disease in humans. Renal involvement usually manifests as a membranoproliferative glomerulonephritis with marked monocyte infiltration and, at times, intracapillary thrombi. Thymic stromal lymphopoietin (TSLP) is a recently cloned cytokine that supports differentiation and long-term growth of B cells. Here we report that TSLP overexpression in mice results in the development of mixed cryoglobulins, with renal involvement closely resembling cryoglobulinemic glomerulonephritis as it occurs in humans. One hundred twenty-three mice were sacrificed at monthly intervals, with at least five TSLP transgenic mice and five controls in each group. Blood, kidneys, spleen, liver, lung, and ear were collected and studied by routine microscopy, immunofluorescence, immunohistochemistry, and electron microscopy. TSLP transgenic animals developed polyclonal mixed cryoglobulinemia (type III) and a systemic inflammatory disease involving the kidney, spleen, liver, lung, and ears. Renal involvement was of a membranoproliferative type demonstrating thickened capillary walls with cellular interposition and double contours of the basement membrane, expansion of the mesangium because of increased matrix and accumulation of immune-deposits, subendothelial immune-deposits, focal occlusion of capillary loops, and monocyte/macrophage influx. In contrast to the severe glomerular lesions, the tubulointerstitium was not involved in the disease process. The renal lesions and the disease course were more severe in females when compared to males. We describe a mouse strain in which a B-cell-promoting cytokine leads to formation of large amounts of mixed cryoglobulins and a systemic inflammatory injury that resembles important aspects of human cryoglobulinemia. This is the first reproducible mouse model of renal involvement in mixed cryoglobulinemia, which enables detailed studies of a membranoproliferative pattern of glomerular injury.

Animals↗
PubMed2001

The effect of cardiopulmonary lymphatic obstruction on heart and lung function.

Many thoracic surgical procedures involve excision or destruction of intrathoracic and mediastinal lymphatics. It is widely assumed that the mediastinal lymphatic system is surgically expendable, and that destruction of mediastinal lymphatics has no significant adverse physiological effect. Cardiac lymphatic obstruction may give rise to cardiac lymphedema and impaired cardiac function. Similarly, obstruction of pulmonary lymphatics may result in pulmonary perivascular lymphedema, endothelial injury, and pulmonary artery hypertension. This review summarizes the possible deleterious effects of intrathoracic lymphatic destruction and the benefits of pharmacological and surgical enhancement of active lymph drainage.

Animals↗
PubMed2001

Novel rhodopsin mutation in a Chinese family with autosomal dominant retinitis pigmentosa.

PURPOSE: To identify mutations in the rhodopsin (RHO) gene in Chinese patients with autosomal dominant retinitis pigmentosa (ADRP) and to measure the prevalence rate of RHO mutations in Chinese ADRP cases. METHODS: Thirteen Chinese families with ADRP were clinically characterized. The complete coding region and intron splice sites of RHO were analyzed for mutations with single-strand conformation polymorphism (SSCP) analysis and direct genomic sequencing. RESULTS: One of the 13 Chinese families with ADRP was found to have a new, previously unidentified RHO mutation, a change from GAG to TAG at codon 341. The mutation (E341X) results in an in-frame stop codon, leading to the truncation of the rhodopsin protein. Mutation E341X was not detected in 100 normal control individuals. Patients carrying mutation E341X reported night blindness and showed optic atrophy, vessel attenuation, and a few bone spicule-like pigments in peripheral retina at the age of 23-25 years. At the age of 30 years, visual acuity was severely impaired, peripheral visual field was greatly constricted, rod and cone ERG was not detectable, and only a slight left cone response remained. CONCLUSIONS: We have identified a novel rhodopsin mutation (E341X) in a Chinese family with ADRP. The location and character of the mutation expand the spectrum of RHO mutations causing RP. Identification of a RHO mutation in one of the 13 ADRP families studied suggests that only 7.7% of the ADRP cases in a Chinese population were caused by RHO mutations, a ratio significantly lower than that from North America or Europe.

Adult↗
PubMed2001

Genetic evidence supports a role for the yeast CCR4-NOT complex in transcriptional elongation.

The CCR4-NOT complex is involved in the regulation of gene expression both positively and negatively. The repressive effects of the complex appear to result in part from restricting TBP access to noncanonical TATAA binding sites presumably through interaction with multiple TAF proteins. We provide here genetic evidence that the CCR4-NOT complex also plays a role in transcriptional elongation. First, defects in CCR4-NOT components as well as overexpression of the NOT4 gene elicited 6-azauracil (6AU) and mycophenolic acid sensitivities, hallmarks of transcriptional elongation defects. A number of other transcription initiation factors known to interact with the CCR4-NOT complex did not elicit these phenotypes nor did defects in factors that reduced mRNA degradation and hence the recycling of NTPs. Second, deletion of ccr4 resulted in severe synthetic effects with mutations or deletions in the known elongation factors RPB2, TFIIS, and SPT16. Third, the ccr4 deletion displayed allele-specific interactions with rpb1 alleles that are thought to be important in the control of elongation. Finally, we found that a ccr4 deletion as well as overexpression of the NOT1 gene specifically suppressed the cold-sensitive phenotype associated with the spt5-242 allele. The only other known suppressors of this spt5-242 allele are factors involved in slowing transcriptional elongation. These genetic results are consistent with the model that the CCR4-NOT complex, in addition to its known effects on initiation, plays a role in aiding the elongation process.

Alleles↗
PubMed2001

Effects of the two-component system comprising GacA and GacS of Erwinia carotovora subsp. carotovora on the production of global regulatory rsmB RNA, extracellular enzymes, and harpinEcc.

Posttranscriptional regulation mediated by the regulator of secondary metabolites (RSM) RsmA-rsmB pair is the most important factor in the expression of genes for extracellular enzymes and HarpinEcc in Erwinia carotovora subsp. carotovora. RsmA is a small RNA-binding protein, which acts by lowering the half-life of a mRNA species. rsmB specifies an untranslated regulatory RNA and neutralizes the RsmA effect. It has been speculated that GacA-GacS, members of a two-component system, may affect gene expression via RsmA. Because expA, a gacA homolog, and expS (or rpfA), a gacS homolog, have been identified in E. carotovora subsp. carotovora, we examined the effects of these gacA and gacS homologs on the expression of rsmA, rsmB, and an assortment of exoprotein genes. The gacA gene of E. carotovora subsp. carotovora strain 71 stimulated transcription of genes for several extracellular enzymes (pel-1, a pectate lyase gene; peh-1, a polygalacturonase gene; and celV, a cellulase gene), hrpNEcc (an E. carotovora subsp. carotovora gene specifying the elicitor of hypersensitive reaction), and rsmB in GacA+ and GacS+ E. carotovora subsp. carotovora strains. Similarly, the E. carotovora subsp. carotovora gacA gene stimulated csrB (rsmB) transcription in Escherichia coli. A GacS- mutant of E. carotovora subsp. carotovora strain AH2 and a GacA- mutant of E. carotovora subsp. carotovora strain Ecc71 compared with their parent strains produced very low levels of rsmB, pel-1, peh-1, celV, and hrpNEcc transcripts but produced similar levels of rsmA RNA and RsmA protein as well as transcripts of hyperproduction of extracellular enzymes (Hex) hexA, kdgR (repressor of genes for uronate and pectate catabolism), rsmC, and rpoS (gene for Sigma-S, an alternate Sigma factor). The levels of rsmB, pel-1, peh-1, celV, and hrpNEcc transcripts as well as production of pectate lyase, polygalacturonase, cellulase, protease, and HarpinEcc proteins were stimulated in GacS- and GacA- mutants by GacS+ or GacA+ plasmids, respectively. The GacA effect on exoenzyme genes and hrpNEcc was abrogated in E. carotovora subsp. carotovora mutants deficient in RsmA and RsmC or RsmA, RsmC, and rsmB RNA. The expression of lacZ transcriptional fusions of rsmB of Erwinia amylovora and Erwinia herbicola pv. gypsophilae was markedly reduced in a GacA- and a GacS- mutant of Pseudomonas syringae pv. syringae. Southern blot hybridization revealed the presence of gacA and gacS homologs in all tested strains of soft-rotting Erwinia spp. and several nonsoft-rotting Erwinia species such as E. amylovora, E. rhapontici, E. herbicola, E. stewartii, and E. herbicola pv. gypsophilae. These findings establish that the GacA-GacS system controls transcription of rsmB of E. carotovora subsp. carotovora, E. amylovora, and E. herbicola pv. gypsophilae and support the hypothesis that the effects of this two-component system on extracellular protein production in E. carotovora subsp. carotovora is mediated, at least in part, via the levels of rsmB transcripts.

Bacterial Outer Membrane Proteins↗
PubMed2001

Bis(2,2-bipyridine-N,N')tetra-mu-chloro-tetracopper(I).

A novel centrosymmetric chair-like dimer, bis(2,2'-bipyridine)-1kappa(2)N,N';3kappa(2)N,N'-tetra-mu-chloro-1:2kappa(2)Cl;2:3kappa(2)Cl;3:4kappa(2)Cl;1:4kappa(2)Cl-tetracopper(I), [Cu(4)Cl(4)(C(10)H(8)N(2))(2)], has been solvothermally synthesized and structurally characterized. The complex self-assembles into a three-dimensional network via C-H.Cl hydrogen bonds, pi-pi stacking and weak Cu.Cl electrostatic interactions.

Journal Article↗
PubMed2001

Strain imaging and elasticity reconstruction of arteries based on intravascular ultrasound video images.

Based on intravascular ultrasound (IVUS) video images, a novel motion estimation method combining the genetic algorithm-based optical flow method and a step-by-step and sum strategy has been developed to estimate the displacement and strain distributions on the scan cross sections of the arteries. And then, real elasticity distributions were reconstructed under the conditions of small and large deformation. Experimental results of in vitro porcine arteries demonstrated the feasibility of the method. This investigation may have potentials to provide new technological means for monitoring and evaluating percutaneous transluminal coronary angioplasty procedure, especially, for the end users of IVUSpercimaging equipment.

Animals↗
PubMed2001

Vectorial transport by double-transfected cells expressing the human uptake transporter SLC21A8 and the apical export pump ABCC2.

Vectorial transport of endogenous substances, drugs, and toxins is an important function of polarized cells. We have constructed a double-transfected Madin-Darby canine kidney (MDCK) cell line permanently expressing a recombinant uptake transporter for organic anions in the basolateral membrane and an ATP-dependent export pump for anionic conjugates in the apical membrane. Basolateral uptake was mediated by the human organic anion transporter 8 (OATP8; symbol SLC21A8) and subsequent apical export by the multidrug resistance protein 2 (MRP2; symbol ABCC2). Under physiological conditions, both transport proteins are strongly expressed in hepatocytes and contribute to the hepatobiliary elimination of organic anions. Expression and localization of OATP8 and MRP2 in MDCK cells growing on Transwell membrane inserts was demonstrated by immunoblotting and confocal laser scanning microscopy. (3)H-Labeled sulfobromophthalein (BSP) was a substrate for both transport proteins and was transferred from the basolateral to the apical compartment at a rate at least six times faster by double-transfected MDCK-MRP2/OATP8 cells than by single-transfected MDCK-OATP8 or MDCK-MRP2 cells. Vectorial transport at a much higher rate by double-transfected than by single-transfected cells was also observed for the (3)H-labeled substrates leukotriene C(4), 17 beta-glucuronosyl estradiol, and dehydroepiandrosterone sulfate, for the fluorescent anionic substrate fluo-3, and for the antibiotic rifampicin. Inhibition studies indicated that intracellular formation of S-(2,4-dinitrophenyl)-glutathione from 2,4-chlorodinitrobenzene selectively inhibits the transcellular transport of [(3)H]BSP at the site of MRP2-mediated export. The double-transfected cells provide a useful system for the identification of transport substrates and transport inhibitors including drug candidates.

Animals↗
PubMed2001

Molecular characterization of global regulatory RNA species that control pathogenicity factors in Erwinia amylovora and Erwinia herbicola pv. gypsophilae.

rsmB(Ecc) specifies a nontranslatable RNA regulator that controls exoprotein production and pathogenicity in soft rot-causing Erwinia carotovora subsp. carotovora. This effect of rsmB(Ecc) RNA is mediated mostly by neutralizing the function of RsmA(Ecc), an RNA-binding protein of E. carotovora subsp. carotovora, which acts as a global negative regulator. To determine the occurrence of functional homologs of rsmB(Ecc) in non-soft-rot-causing Erwinia species, we cloned the rsmB genes of E. amylovora (rsmB(Ea)) and E. herbicola pv. gypsophilae (rsmB(Ehg)). We show that rsmB(Ea) in E. amylovora positively regulates extracellular polysaccharide (EPS) production, motility, and pathogenicity. In E. herbicola pv. gypsophilae, rsmB(Ehg) elevates the levels of transcripts of a cytokinin (etz) gene and stimulates the production of EPS and yellow pigment as well as motility. RsmA(Ea) and RsmA(Ehg) have more than 93% identity to RsmA(Ecc) and, like the latter, function as negative regulators by affecting the transcript stability of the target gene. The rsmB genes reverse the negative effects of RsmA(Ea), RsmA(Ehg), and RsmA(Ecc), but the extent of reversal is highest with homologous combinations of rsm genes. These observations and findings that rsmB(Ea) and rsmB(Ehg) RNA bind RsmA(Ecc) indicate that the rsmB effect is channeled via RsmA. Additional support for this conclusion comes from the observation that the rsmB genes are much more effective as positive regulators in a RsmA(+) strain of E. carotovora subsp. carotovora than in its RsmA(-) derivative. E. herbicola pv. gypsophilae produces a 290-base rsmB transcript that is not subject to processing. By contrast, E. amylovora produces 430- and 300-base rsmB transcripts, the latter presumably derived by processing of the primary transcript as previously noted with the transcripts of rsmB(Ecc). Southern blot hybridizations revealed the presence of rsmB homologs in E. carotovora, E. chrysanthemi, E. amylovora, E. herbicola, E. stewartii and E. rhapontici, as well as in other enterobacteria such as Escherichia coli, Salmonella enterica serovar Typhimurium, Serratia marcescens, Shigella flexneri, Enterobacter aerogenes, Klebsiella pneumoniae, Yersinia enterocolitica, and Y. pseudotuberculosis. A comparison of rsmB sequences from several of these enterobacterial species revealed a highly conserved 34-mer region which is predicted to play a role in positive regulation by rsmB RNA.

Amino Acid Sequence↗
PubMed2001

Digital optical imaging of green fluorescent proteins for tracking vascular gene expression: feasibility study in rabbit and human cell models.

PURPOSE: To investigate the feasibility of using a sensitive digital optical imaging technique to detect green fluorescent protein (GFP) expressed in rabbit vasculature and human arterial smooth muscle cells. MATERIALS AND METHODS: A GFP plasmid was transfected into human arterial smooth muscle cells to obtain a GFP-smooth muscle cell solution. This solution was imaged in cell phantoms by using a prototype digital optical imaging system. For in vivo validation, a GFP-lentivirus vector was transfected during surgery into the carotid arteries of two rabbits, and GFP-targeted vessels were harvested for digital optical imaging ex vivo. RESULTS: Optical imaging of cell phantoms resulted in a spatial resolution of 25 microm/pixel. Fluorescent signals were detected as diffusely distributed bright spots. At ex vivo optical imaging of arterial tissues, the average fluorescent signal was significantly higher (P <.05) in GFP-targeted tissues (mean +/- SD, 9,357.3 absolute units of density +/- 1,001.3) than in control tissues (5,633.7 absolute units of density +/- 985.2). Both fluorescence microscopic and immunohistochemical findings confirmed these differences between GFP-targeted and control vessels. CONCLUSION: The digital optical imaging system was sensitive to GFPs and may potentially provide an in vivo imaging tool to monitor and track vascular gene transfer and expression in experimental investigations.

Animals↗
PubMed2001

Nitric oxide-mediated arteriolar dilation after endothelial deformation.

Previously, we frequently observed dilation of arterioles after agonist-induced constrictions. We hypothesized that deformation of the endothelium during decreases in diameter of isolated arterioles elicits the release of nitric oxide (NO). In isolated arterioles of rat mesentery, phenylephrine (PE, 10(-7) M)-, U-46619 (10(-7) M)-, and KCl (50 mM)-induced constrictions were followed by potent dilations. Inhibition of NO synthase with N(omega)-nitro-L-arginine (L-NNA, 2 x 10(-4) M) or removal of the endothelium significantly enhanced constriction and reduced the postconstriction dilation. In the presence of 80 mmHg of intraluminal pressure, an increase in extraluminal pressure (P(e)) to 75 mmHg for 20 s and 1 and 2 min decreased vessel diameter. After release of P(e), arterioles dilated as a function of the duration of diameter reduction by P(e). Removal of the endothelium or administration of L-NNA significantly diminished the post-P(e) dilations. In cultured mesenteric arteriolar endothelial cells (EC), PE, U-46619, or KCl did not increase, whereas ACh did increase, the production of NO, as measured by a fluorometric assay for nitrite. Furthermore, when EC, cultured on a stretched silicone membrane, were subjected to deformation by shortening the membrane to 50% of its original length, NO release increased significantly. Based on all of the above, we propose that deformation of EC per se elicits release of NO, a mechanism that modulates arteriolar constriction.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed2001

Tartary buckwheat flavonoid activates caspase 3 and induces HL-60 cell apoptosis.

It has been proposed that flavonoids may have potential as anticancer agents. In this study, we showed that tartary buckwheat flavonoid (TBF) obviously inhibits the growth of human acute myelogenous leukemia (AML) HL-60 cells by MTT assay. The inhibitory effect of TBF on the proliferation of HL-60 cells is related to the induction of apoptosis, which is confirmed by DNA ladder formation on gel electrophoresis and apoptosis morphological changes under light microscope. Furthermore, HL-60 cells undergo rapid apoptosis upon treatment with TBF, as indicated by increased annexin V binding capacity and caspase 3 activation with flow cytometric analysis. Thus, our data provide a potential mechanism for the chemopreventive activity of tartary buckwheat flavonoid and suggest that it may have a potentially therapeutic role for human leukemia.

Annexin A5↗
PubMed2001

Reduction of dehydroerythorbic acid in vitamin C-deficient guinea pigs.

A reduction of dehydroerythorbic acid (DERA) to erythorbic acid (ERA) in vitamin C-deficient guinea pigs was evaluated and compared with that of dehydroascorbic acid (DASA). Thirty-six guinea pigs were fed with vitamin C-deficient diets for 18 days. On day 19, the guinea pigs were divided into four groups for the administration of 100 mg of DERA, ERA, ascorbic acid (ASA), or DASA every day. After 12 days of oral administration, the concentration of DERA, ERA, ASA, and DASA in the liver, adrenal, spleen, kidney, and plasma of guinea pigs was determined by HPLC. A recovery from scurvy was measured in terms of weight gain and serum alkaline phosphatase activity. All four groups showed similar recovery, indicating that the oral administration of relatively high concentrations of DERA reversed the effects of scurvy in vitamin C-deficient guinea pigs. In spite of DERA or DASA administration, ERA or ASA was mainly detected in the tissues. The reduction ratios of DEAR and DASA were similar (approximately 80%) in all tissues except spleen. These results suggest that both DASA and DERA are taken up and reduced to ASA or ERA in vivo.

Animals↗
PubMed2001

Expression of chemokines and chemokine receptors during human renal transplant rejection.

Infiltration of renal allografts by leukocytes is a hallmark of acute transplant rejection. Chemokines attract leukocytes bearing specific chemokine receptors, and the specific leukocyte chemokine receptor phenotype is associated with types of immune responses, ie, T helper subtype 1 (Th1; CXC chemokine receptor 3 [CXCR3], CC chemokine receptor 5 [CCR5]) versus Th2 (CCR3, CCR4, CCR8). We studied the expression of the chemokine monocyte chemoattractant protein-1 and the chemokine receptors CCR2B and CXCR4 messenger RNA (mRNA) by in situ hybridization, as well as the chemokine receptors Duffy antigen receptor for chemokines (DARC) and CCR5 protein by immunohistochemistry in renal biopsy specimens with acute cellular rejection (n = 12) and acute vascular rejection (n = 8), transplant nephrectomy specimens (n = 6), and normal areas of tumor nephrectomy specimens (n = 5). CC chemokines and CC chemokine receptor mRNA expression were evaluated by ribonuclease protection assay in specimens from four transplant nephrectomies and one tumor nephrectomy. Upregulation of mRNAs for the chemokines, interferon-inducible protein-10 (IP-10); regulated on activation normal T-cell expressed and secreted; macrophage inflammatory protein-1alpha (MIP-1alpha); MIP-1beta; and lymphotactin, as well as the chemokine receptors, CCR2 and CCR5, were documented during allograft rejection. CCR1 mRNA was detectable in both allografts and controls, but CCR3 and CCR8 were absent. The number of CXCR4, CCR5, and CCR2B mRNAs expressing leukocytes and DARC-positive vessels increased during rejection episodes. CXCR4 mRNA was the most widely expressed. Leukocytes in diffuse interstitial infiltrates were mainly CCR5 positive, but in areas in which leukocytes formed nodular aggregates of infiltrating cells, the number of CCR5-positive cells was low. Instead, leukocytes in these nodular aggregates mainly expressed CXCR4. DARC was expressed on peritubular capillaries, where it was upregulated in areas of interstitial infiltration. Induction of chemokines during renal allograft rejection is accompanied by infiltration of leukocytes bearing the respective chemokine receptors. The upregulation of the CXCR3 ligand IP-10, as well as CCR5 and its ligands, in the absence of CCR3 and CCR8 is indicative that renal allograft rejection is primarily the result of a Th1-type immune response.

Antigens, Protozoan↗
PubMed2001

Effect and mechanism of electronic magnetic pulse on peripheral lymphocytes in dogs.

OBJECTIVE: To study the effects of electronic magnetic pulse (EMP) on peripheral lymphocytes in dogs and to explore the mechanisms of the biological effects of EMP. METHODS: T, TH and TS lymphocytes were estimated by acid phosphatase cytochemistry. Apoptotic lymphocytes and Bax and Bcl-2 proteins related to apoptosis were observed with in situ terminal labeling and immunocytochemistry. RESULTS: Peripheral T lymphocyte subpopulations decreased obviously after EMP irradiation with (2-12) x 10(4) V/m. Apoptotic percentages of lymphocytes increased with the elevation of EMP doses. Ten days after different intensity radiation, the Bax protein was found to be elevated in accord with the peak value of lymphocyte apoptosis. However, Bcl-2 protein decreased obviously. CONCLUSION: A definite field intensity EMP could induce injury to lymphocytes. Apoptosis induced by EMP is one of the main causes of peripheral lymphocyte death and leads to immunosuppression of the body. These results suggest that people should pay more attention to the injury caused by EMP, especially to the immunological functions of the body.

Animals↗
PubMed2001

[Development of a diagnostic kit of enzyme-linked immunoassay for detecting serum anti-hepatitis E virus IgG].

OBJECTIVE: To develop a diagnostic kit for detecting serum anti-hepatitis E virus (HEV) IgG with enzyme-linked immunoassay (ELISA). METHODS: The diagnostic kit of detecting anti-HEV IgG with ELISA was prepared by two synthetic HEV peptides used for coating the solid-phase to capture the antibody against HEV in serum, and then by horseradish peroxidase antihuman IgG (gamma chain) added as the second antibody to bind the anti-HEV IgG in serum. Its sensitivity, specificity, precision and stability were measured and clinically evaluated. RESULTS: The sensitivity, specificity, and precision of the diagnostic kit detected by the China National Institute for the Control of Pharmaceutical and Biological Products were 90% (1/10), 100% (0/30) and < 15%, respectively, meeting the national standards for detecting serum anti-HEV IgG with ELISA. The ELISA Kit is stable for 1 year at least under 4 degrees C. The total consistency rates were 100% (43/43) and 96.6% (86/89), as compared with Genelabs and Singaporean DBL kits. This diagnostic kit for detecting serum anti-HEV IgG with ELISA was evaluated and approved by the State Drug Administration, China and a certificate was conferred in 1998. CONCLUSIONS: The diagnostic kit for detecting anti-HEV IgG with ELISA can be used for epidemiological studies and clinical diagnosis of HEV infection.

Antibodies, Viral↗