Biomedical subjects

Y Deng

Publications and source records attributed to Y Deng.

At least 181 records · Page 10Linked to original sources

PubMed1995

Mechanism of the tumor necrosis factor alpha-mediated induction of endothelial tissue factor.

This study examines the regulation of the human tissue factor (TF) promotor in vitro and in vivo. Transient transfections were performed in bovine aortic endothelial cells to investigate the role of two fundamentally different AP-1 sites and a closely located NF-kappa B site in the human TF promoter. The NF-kappa B site is functionally active, since overexpression of NF-kappa B(p65) resulted in induction of TF mRNA and activity. Promoter analysis showed that NF-kappa B induction was dependent on the integrity of the region from base pair -188 to -181. Over-expression of Jun/Fos resulted in TF induction of transcription and protein/activity. Functional studies revealed that the proximal AP-1 site, but not the distal, was inducible by Jun/Fos heterodimers. The distal AP-1 site, which has a G-->A switch at position 4, was inductible by Jun homodimers. Electrophoretic mobility shift assays, using extracts of tumor necrosis factor alpha (TNF alpha)-stimulated bovine aortic endothelial cells, demonstrated TNF alpha-inducible binding to the proximal AP-1 site, comprising JunD/Fos heterodimers. At the distal AP-1 site, only minor induction of binding activity, characterized as proteins of the Jun and ATF family, was observed. Consistently, this site only marginally participates in TNF alpha induction. Functional studies with TF promotor plasmids confirmed that deletion of the proximal AP-1 or the NF-kappa B site decreased TNF alpha-mediated TF induction to a higher extend than loss of the distal AP-1 site. However, integrity of both AP-1 sites and the NF-kappa B site was required for optimal TNF alpha stimulation. The relevance of these in vitro data was confirmed in vivo in a mouse tumor model. Expression plasmids for a dominant negative Jun mutant or I-kappa B were packaged in liposomes. When either mutated Jun or I-kappa B were injected intravenously 48 h before TNF alpha, a reduction in TNF alpha-mediated TF expression in the tumor endothelial cells was observed. Simultaneously, fibrin/fibrinogen deposition decreased and free blood flow could be restored. Thus, TNF alpha-induced up-regulation of endothelial cell TF depends on a concerted action of members of the bZIP and NF-kappa B family.

Animals↗

PubMed1995

Determination of the (R)- and (S)-enantiomers of salsolinol and N-methylsalsolinol by use of a chiral high-performance liquid chromatographic column.

A new method for the quantitative determination of the enantiomers of salsolinol and N-methylsalsolinol, biologically important alkaloids, is reported. The enantiomers were completely separated without derivatization, using a cyclodextrin-modified silica gel column with an HPLC-electrochemical detection system. The HPLC conditions were examined for the best resolution. The method was sensitive enough to detect salsolinol and N-methylsalsolinol at a concentration of less than 0.1 pmol per injection. In the product of the Pictet-Spengler reaction of acetaldehyde with dopamine or epinine, almost equimolar (R)- and (S)-enantiomers of salsolinol and N-methylsalsolinol were detected. Preliminary results indicate that the (R)-enantiomer of both isoquinoline derivatives predominate in the human brain.

Chromatography, High Pressure Liquid↗

PubMed1995

Induction of TCR-gamma delta expression on triple-negative (CD3-4-8-) human thymocytes. Comparative analysis of the effects of IL-4 and IL-7.

It is well established that IL-4 and IL-7 control the differentiation of TCR-gamma delta-expressing cells from CD3/TCR-negative thymic precursors. In this study, we have compared the in situ expression of IL-4 and IL-7 mRNA in human postnatal thymus with the in vitro effect of IL-4 and IL-7 on the expansion of TCR-gamma delta + cells from highly purified CD3-4-8- triple-negative thymocytes. IL-4 mRNA expression was restricted to subcapsular regions of the human thymus, whereas cells expressing IL-7 mRNA were distributed throughout the thymic tissue, with some enrichment in subcapsular and cortical regions. Epithelial cells of the outer layer of Hassall's corpuscle strongly expressed IL-7 mRNA. IL-7 but not IL-4 or IL-2, stimulated strong proliferative activity and cellular expansion of triple-negative thymocytes. All three induced the appearance of TCR-gamma delta + cells within 4 days of culture. In the presence of IL-4 or IL-2, 30 to 55% of viable cells were TCR-gamma delta + after 5 to 9 days, whereas only 10 to 15% triple-negative thymocytes cultured with IL-7 expressed TCR-gamma delta. However, comparable absolute numbers of viable TCR-gamma delta + thymocytes were recovered when triple-negative thymocytes were cultured with IL-4 or IL-7, but not with IL-2. Taken together, our results suggest that IL-4 and IL-7 (both of which are produced in situ in thymic tissue) play equally important roles in the in vitro generation of TCR-gamma delta + thymocytes from triple-negative precursor cells.

Gene Expression↗

PubMed1995

Polymerase chain reaction detection of small round-structured viruses from two related hospital outbreaks of gastroenteritis using inosine-containing primers.

Two outbreaks of gastroenteritis in the UK which occurred nine days apart at Lymington and Southampton hospitals were investigated. The clinical and epidemiological features of both outbreaks were characteristic of small round-structured virus (SRSV) infection with rapid onset of diarrhoea and/or nausea and vomiting and propagation of the outbreaks by secondary spread. SRSV particles were observed by immune electron microscopy (EM) in 60% of faecal samples from both outbreaks and no other pathogens were detected. The index case for the second outbreak was a patient who was admitted with diarrhoea and vomiting after being discharged from Lymington hospital during the first outbreak. The possibility that the two outbreaks were caused by the same strain of SRSV was investigated by the polymerase chain reaction (PCR). New inosine-containing PCR primers were designed to amplify the RNA polymerase region of SRSV cDNA from genetic groups I and II. The PCR using the group II primers achieved a higher detection rate for SRSVs in faecal samples (68% of samples positive from both outbreaks) than immune EM. SRSVs were not detected using the group I primers or using conventional degenerate PCR primers. The nucleotide sequences of PCR amplicons from both outbreaks were identical providing molecular epidemiological evidence for the involvement of a single SRSV strain. Comparison of the RNA polymerase region of this virus with the equivalent regions of genetic group I (69.4-75.0% amino acid identify) and genetic group II (88.9-100% amino acid and 77.1-88.1% nucleotide identity) SRSVs revealed that the causative SRSV was a distinct member of genetic group II.

Amino Acid Sequence↗

PubMed1995

Molecular characterization of the 11th RNA segment from human group C rotavirus.

The complete nucleotide sequence of genome segment 11 from the noncultivatable, human group C rotavirus (Bristol strain) was determined. Comparison of the nucleotide sequence of the segment termini with the consensus 5' and 3' terminal noncoding sequences of the human group C rotavirus genome revealed characteristic 5' and 3' sequences. Human group C rotavirus genome segment 11 is 613 bp long and encodes a single open reading frame of 450 nucleotides (150 amino acids) starting at nucleotide 39 and terminating at nucleotide 489, leaving a long 3' untranslated region of 124 nucleotides. The predicted translation product has a calculated molecular weight of 17.7 kD and contains four potential N-linked glycosylation sites. No significant homologies to other viral proteins were found in database searches. Hydropathy analysis predicted the human group C rotavirus genome segment 11 translation product has a hydrophilic carboxy terminus (amino acids 54-150) and a hydrophobic amino terminus (amino acids 1-53) that can be further subdivided into three short hydrophobic sequences--H1, H2, and H3. These features are analogous to the integral membrane glycoprotein NSP4 encoded by group A rotavirus gene 10.

Amino Acid Sequence↗

PubMed1995

Enzymatic oxidation of the dopaminergic neurotoxin, 1(R), 2(N)-dimethyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, into 1,2(N)-dimethyl-6,7-dihydroxyisoquinolinium ion.

The dopamine-derived alkaloid, 1(R),2(N)-dimethyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline [N-methyl(R)salsolinol] was found to be oxidized enzymatically into the more cytotoxic species, 1,2(N)-dimethyl-6,7-dihydroxyisoquinolinium ion, using enzyme sample prepared from human brain cortex. The values of the Michaelis constant and of the maximum velocity were 912 microM and 1,368 pmol/min/mg protein, respectively. The enzyme was not inhibited by inhibitors of monoamine oxidase, but was sensitive to semicarbazide. The oxidation is discussed in relation to the dopaminergic neurotoxicity of N-methyl-(R)salsolinol.

Cell Compartmentation↗

PubMed1995

A novel natriuretic, hypotensive factor derived from the spleen.

Previous experiments have shown that the reduction in plasma volume observed after administration of atrial natriuretic factor is abolished by splenectomy. In order to determine whether the spleen contains a factor that influences cardiorenal homeostasis, rat spleens were homogenized in phosphate-buffered saline, centrifuged, subjected to ultrafiltration (molecular weight cut-off 10,000), extracted on C18 affinity columns and dried. After reconstitution in isotonic saline, the extract was injected i.v. into conscious rats. In response to this extract, there was a dose-dependent diuresis, natriuresis, kaliuresis and chloruresis which plateaued during the second and third hours following administration. Solute-free water clearance was inversely related to urine output. Blood pressure fell significantly from 109 +/- 3 mm Hg to 103 +/- 3 mm Hg during the first 10 min. after injection of the extract, and tended to remain depressed thereafter. There was no accompanying increase in heart rate. We conclude that the mammalian spleen contains a natriuretic, hypotensive factor that may play a role in cardiorenal homeostasis.

Animals↗

PubMed1995

Heterogeneity of enteroaggregative Escherichia coli virulence demonstrated in volunteers.

Enteroaggregative Escherichia coli (EAggEC) are diarrheal pathogens defined by aggregative adherence to HEp-2 cells. In an effort to identify pathogenic EAggEC isolates, four groups of 5 volunteers were fed 1 of 4 different EAggEC strains, each at a dose of 10(10) cfu. Strain 042 caused diarrhea in 3 of 5 adults; 3 other EAggEC isolates (17-2, 34b, and JM221) failed to elicit diarrhea. A gene encoding enterotoxin EAST1 was found in strains 042 and 17-2 but not 34b or JM221; a 108-kDa cytotoxin was expressed in all 4 isolates. All 4 isolates showed a modest degree of gentamicin protection in HEp-2 cells. 17-2, 34b, and JM221 expressed the fimbrial antigen AAF/I; 042 did not express this fimbria as determined by immunogold electron microscopy and genetic probe hybridization.

Bacterial Adhesion↗

PubMed1995

Effect of pregnancy on activation of central pathways following atrial distension.

Stimulation of the atrial volume receptors increases neural traffic to the ventrolateral medulla, which in turn sends output to, and receives input from, the lateral hypothalamic area. An integrated reflex and hormonal response is thus initiated. We wished to investigate first whether atrial distension results in activation of selected nuclei in the forebrain and, second, whether pregnancy modifies this response. Rats were implanted with indwelling intracardiac balloons positioned at the superior vena caval/right atrial junction. One week later, the balloons were inflated. The animals were then anesthetized, their brains fixed by perfusion, and the tissue prepared for visualization of c-fos activity. Atrial distension caused a significant increase in c-fos expression in the paraventricular nucleus, the medial preoptic area, and the lateral septum. This response was markedly attenuated in the pregnant animals. In conclusion, during pregnancy central pathways that are normally activated in responses to volume expansion, fail to respond to atrial distension. We propose that this allows blood volume to increase in the pregnant animal, without triggering homeostatic mechanisms.

Animals↗

PubMed1995

Fluorescent conjugates of brefeldin A selectively stain the endoplasmic reticulum and Golgi complex of living cells.

The fungal metabolite brefeldin A (BFA) interferes with vesicular trafficking in most animal cells. To gain insight into the mechanism of BFA action, we esterified it to the fluorophore, boron dipyromethene difluoride (BODIPY). BODIPY-BEA localized predominantly in the endoplasmic reticulum (ER) and Golgi complex of viable cells and was extracted by detergent treatment, suggesting it interacts primarily with lipid bilayers. The localization of the conjugate is conferred by BFA, since free BODIPY or BODIPY esterified to cyclopentanol did not specifically localize to internal membranes. BODIPY-BFA exhibited a similar biological activity to BFA, but only when used at higher concentrations and after a delay. HPLC analysis revealed that over this period, cells converted BODIPY-BFA to species co-eluting with free BODIPY and BFA. Therefore, BODIPY-BFA is probably inactive until BFA is released by cellular esterases. The specific localization of BODIPY-BFA to the ER and Golgi complex suggests that BFA might exert its effects on vesicular trafficking by perturbing the lipid bilayer of its target organelles. Because BODIPY-BFA intensely stains the ER at concentrations that have no discernible effects on intracellular transport or other cellular functions, it should be useful for visualizing the ER in living cells.

Animals↗

PubMed1995

[Some biochemical indexes in white rabbit's blood affected by acute high intensity microwave].

Irradiation of white rabbits by 10, 50, 100 and 200 mW/cm2 microwave respectively can cause the disorder of protein metabolism, the abnormality of blood sugar, and the change of the activity of serum alpha-hydroxybutyrate dehydrogenase, lactate dehydrogenase, glutamic oxalacetic transaminase, glutamic pyruvic transaminase, acid phosphatase ect. These changes can be used as indexes in the evaluation of the effect of acute high intensity microwave exposure. The effect on the organism mainly depends on the intensity of exposure provided the dose of microwave remains the same.

Acid Phosphatase↗

PubMed1995

[Change of the guaning nucleotide-regulating protein in substantia gelatinosa of spinal cord of rats after unilateral transection of dorsal roots and electroacupuncture: an immunohistochemical observation].

The Subunit alpha o of guanine nucleotide-binding protein (rabbit polyclonal antiserum 9120, K,J. Chang. USA), in the areas of rat spinal cord was localized by immunohistochemical PAP methods, and the changes of alpha o-immunoreactivity (alpha o-IR) in the substantia gelatinosa (SG) were observed after unilateral transection of dorsal roots and electroacupuncture. Intense alpha o-IR was presented in Rexed lamina I to III of the dorsal horn, and the highest alpha o-IR in lamina (SG), which was found than that in the normal and control animals. Iateral spinal nucleus of rat revealed higher density of alpha o-IR containing fiber networks. Following unilateral transection of dorsal roots and pain threshold increased significantly after electroacupuncture applied at the point "Huantiao", alpha o-IR was markedly decreased than that in the normal and control group in those areas. The optic density (OD) of alpha o-IR were measured, which decreased more markedly in opration and electroacupuncture group than that normal and control group. The results mentioned above indicate that Go-protein in terminals of primary nociceptive neurons of SG decreases markedly after dorsal roots transected and electroacupuncture. It was inferenced that partial Go-protein probably originates from the primary sensory neurons, and the release of "inhibitory" of Go may increase (with weaker alpha o-IR). In a work, Go might play important roles on the primary afferents informational regulation and electroacupuncture analgesia of the regulation.

Animals↗

PubMed1995

Expression of receptors for advanced glycation end products in peripheral occlusive vascular disease.

The cellular interactions of advanced glycation end products (AGEs), which have been hypothesized to contribute to the development of vascular lesions, occur, at least in part, through their binding to a novel integral membrane protein, the receptor for AGEs (RAGE). Studies of human vascular segments show that endothelial RAGE expression at the antigen and mRNA level was variable and usually at low levels in samples from healthy individuals. In contrast, patients with a range of peripheral occlusive vascular diseases, with or without underlying diabetes, demonstrated prominent enhancement of endothelial RAGE expression. Smooth muscle cells and nerves in the vessel wall showed constitutively high levels of RAGE expression that were unchanged with aging (from 1 to 92 years) or by the presence of vascular disease. These data suggest that RAGE is likely to have ligands other than AGEs, and that multiple factors in addition to AGEs impact on its expression. Taken together, our findings suggest that RAGE may contribute to the pathogenesis of a range of vascular disorders.

Adult↗

PubMed1995

Expression of receptors for advanced glycosylated end-products in renal disease.

BACKGROUND: Advanced glycation endproducts (AGEs) are believed to mediate long-term complications in diabetes mellitus. In this context we studied the expression of the receptor for AGEs (RAGE) in the kidney of patients with a variety of different renal diseases. METHODS: RAGE was detected by immunocytochemistry in renal biopsies. We compared the staining for RAGE in nine patients with diabetic nephropathy, 20 with inflammatory and/or immune complex and 10 with non-inflammatory renal diseases. Normal renal tissue from seven patients with tumour nephrectomies served as controls. RESULTS: In controls the only cells expressing RAGE constitutively were interstitial cells and vascular smooth muscle cells (6/7), while distal tubular cells were rarely positive (1/7). Endothelial cells of arteries/arterioles, glomerular endothelial cells, podocytes, and capsular epithelial cells were consistently negative. In diabetic nephropathy, inflammatory and/or immune complex, and non-inflammatory renal diseases, all cell types mentioned above became positive for RAGE. Whilst the distribution of RAGE in the tissue was quite similar, staining intensity in inflammatory and/or immune complex diseases was higher than in diabetic nephropathy. CONCLUSION: RAGE induction in the kidney is not specific for diabetic nephropathy and occurs in other types of renal diseases as well.

Adolescent↗

PubMed1995

The modality of huoxue-huayu in treatment of retinal vein occlusion.

BACKGROUND: There were some reports in China about Huoxue-Huayu therapy on retinal vein occlusion (RVO), but prospective and systematic studies are very few. The curative effect and mechanism of this therapy on RVO have not been reported previously. METHODS: 80 patients with RVO were randomly divided into 2 groups, Fundus III (group A) and urokinase group (group B). Group A was treated by Fundus III oral liquid (a composite herbal recipe for Huoxue-Huayu or invigoration of blood circulation and reduction of blood stasis) 10ml/time P.O. t.i.d. The treatment course was 1 mouth. Group B was treated by urokinase. The urokinase that produced in China was used 10,000 u + 5% glucose 500ml/day i.v. drip for 5 days in a course, the rest 5 days going on another course. The total treatment courses lasted 1 month, too. RESULTS: The visual acuity in group A was remarkably improved while that in group B did not change. The extravasated retinal blood was evidently absorbed in 92.7% of the cases in group A and in 66.7% of those in group B. The difference was significant. Fundus III also improved the retinal circulation, decreased the whole blood viscosity and fibrinogen and reduced leakage of the retinal capillaries. The total effective rates were 83.7% in group A and 53.7% in group B with significant statistical difference between the 2 groups (P < 0.01). CONCLUSION: Fundus III may alleviate retinal edema and necroses, improve the recovering of visual acuity, the retinal microcirculation, the rate of absorbing of retinal haemorrhage and treat RVO, and the curative effect is better than urokinase.

Adult↗

PubMed1995

Tissue factor expression in an animal model of hydronephrosis.

BACKGROUND: Hydronephrosis is associated with interstitial fibrosis and occlusion of renal capillaries by fibrin. However, the mechanisms leading to fibrin formation is unknown. METHODS AND RESULTS: Twenty days after unilateral ligation of the ureter, interstitial fibrosis occurred in the ligated kidney. Fibrosis was preceded by infiltration of inflammatory cells (macrophages, B and T lymphocytes). Staining with an antibody against von Willebrand factor demonstrated newly formed capillaries in the fibrosing tissue as well as prominent fibrin deposition. Fibrin staining was found around vessels, in the interstitium, the glomeruli, and tubuli. Fibrin deposition was less prominent in the non-ligated kidney and almost absent in sham-operated animals. The expression of tissue factor, the central initiator of coagulation, was induced within 5 days after ligation in the operated kidney but not in the sham-operated animals. Tissue factor positivity was observed by immunohistochemistry in vascular endothelial cells, the vessel wall, tubular epithelial cells, glomerular capsular cells, Bowman's space and in the interstitium. Tissue factor induction was due to increased transcription, since in-situ hybridization showed increased levels of mRNA in the ligated kidney compared to sham-operated rats. The tissue factor gene is under control of the transcription factors activator protein-1 (AP-1) and nuclear factor-kappa B (NF-kappa B). When extracts of operated organs were compared with kidneys of sham-operated rats or contralateral kidneys in electrophoretic mobility shift assays, an increase in AP-1 and NF-kappa B binding activity to their respective binding sites in the tissue factor gene was observed in the operated, but not in the contralateral kidney or kidneys of sham-operated animals. CONCLUSION: Ureteral ligation leads to infiltration of inflammatory cells, increased AP-1 and NF-kappa B expression in the kidney, resulting in increased tissue factor transcription and translation, and ultimately in increased fibrin deposition.

Animals↗

PubMed1995

Effect of restorative materials on cuspal flexure.

The purposes of this study were (1) to establish a methodology for determining surface strains in two locations of the same tooth under intact, prepared, and restored conditions and (2) to compare the effects on stiffness of different restorative materials in a tooth subjected to cuspal loading. Two linear strain gauges were mounted on each of 30 extracted maxillary premolar teeth. Teeth were mounted in poly(methyl methacrylate) resin and randomly assigned to one of three study groups according to the restorative material and application technique to be used. Statistical analysis indicated a statistically significant interaction between restorative material and tooth condition at both proximal and buccal sites and a statistically significant difference in stiffness between teeth restored with Tenure/Marathon V and those restored with either amalgam or Scotchbond 2/P-50 at the proximal site. Results suggest that the methods employed provide a useful, nondestructive means of testing the same tooth under various conditions.

Analysis of Variance↗

PubMed1995

Dopaminergic (4aR,10bS)-cis- and (4aS,10bS)-trans-octahydrobenzo[F]quinolines have similar pharmacophores.

The structures and absolute configurations of two N-phenethyl substituted cis- and trans-octahydrobenzo[f]quinolines were determined by X-ray crystallography. The absolute configurations of the enantiomers that have high affinity for dopaminergic receptors were found to be (4aR,10bS) and (4aS,10bS) for the (-)-cis- and (-)-trans-8,9-dihydroxy substituted compounds. This is consistent with previous results for a dopamine agonist pharmacophore. MM2-87 calculations for a cis isomer, which has two alternative chair conformations of the piperidine ring, indicated that the preferred conformer is the same as that observed in the crystal structure. Superposition of the more active cis and trans enantiomers showed that the three dimensional orientations of the phenyl ring and the ammonium group are similar in the two geometrical isomers. The cis isomer, however, has steric bulk out of the plane of the molecule and this appears to result in a loss of agonist efficacy. The addition of the N-phenethyl group to the 7-OH and 7,8-diOH cis compounds, however, appears to be sufficient to restore high affinity for dopaminergic receptors unlike previously synthesized cis compounds. These cis compounds, however, appear to be mixed agonist/antagonists or antagonists on functional assays of dopaminergic activity.

Benzoquinones↗