Biomedical subjects

Zhen Wang

Publications and source records attributed to Zhen Wang.

115 records · Page 7Linked to original sources

PubMed2002

[Abnormality of p15(INK4b) gene and myelodysplastic syndrome].

Among tumor suppressor genes, p15(INK4b) gene is gaining more attention for its important role in the progression of myelodyplastic syndrome (MDS). Serial studies demonstrated that highly frequent hypermethylation of p15(INK4b) gene, which is located at the 5'CpG island in the promoter region of exon 1 and is the main reason of inactivation of p15(INK4b) gene, occurs during the development of MDS towards AML. The assay of methylation-specific PCR (MSP) is sensitive to this pattern of methylation which is restricted to the MDS clone. Apoptosis mediated by cytokines such as Fas antigen and TGF-beta, and bHLH proteins is inhibited by the inactivation of p15(INK4b) gene. This may result in the evolution of MDS clone to AML. In as much as the close relationship between p15(INK4b) gene methylation and MDS, modulation of the methylation status of p15(INK4b) gene may be considered as a noval treatment modality for MDS.

Cell Cycle Proteins↗

PubMed2002

[Influence of endothelial cells on the proliferation of scar-derived fibroblast in hypertropic scar tissue].

OBJECTIVE: To investigate the influence of the endothelial cells on the scar-derived fibroblasts in the hypertropic scar tissue. METHODS: The endothelial cell from the human umbilical vein was cultured and its supernatant was then collected. Thereafter, it was mixed with the pre-cultured scar-derived fibroblasts from the hypertropic scar tissue. The fibroblasts were analyzed with a flow cytometer in a MTT-assay method to evaluate the cell proliferation and its division cycle. RESULTS: The endothelial cells were significantly increasing the scar-derived fibroblast proliferation (P < 0.05), compared with the control. The proportion of the fibroblasts in the S-stage of cell cycle was also quite high. CONCLUSION: The endothelial cells may secrete some active products, which may enhance the proliferation of the scar-derived fibroblasts and stimulate the fibroblasts into the S-stage of cell generation cycle.

Cell Cycle↗

PubMed2002

[Automatic ECG analysis system based on TMS320F206].

An automatic ECG analysis system based on DSP is introduced in this paper. It can fulfill the functions of signal regulation, adaptive filtering, QRS waves positioning, and automatically recognize more than 10 kinds of arrhythmia and report alarm. TI DSP product--TMS320F206 is applied in this system to accomplish the adaptive filtering and automatic diagnosis of arrhythmia for the need of real time signal processing.

Adaptation, Physiological↗

PubMed2002

[A new compositive algorithm of ST-segment].

In this paper we introduce a new algorithm about ST-segment--Triangle way. At the same time, based on analyzing all kinds of algorithms, we have summarized a compositive algorithm used to detect the emulating data. The testing result shows that the algorithm, which is easy to use, has a high speed and a good accuracy.

Algorithms↗

PubMedDate not supplied

Synthesis and fluorescence properties of the europium(III) chelate of a polyacid derivative of terpyridine.

A new polyacid derivative ligand of biphenyl-substituted terpyridine, [4'-(biphenyl-4'''-yl)-2,2':6'2''-terpyridine-6,6''-diyl]bis(methylenenitrilo)tetrakis(acetic acid) was synthesized, and the fluorescence properties of its Eu3+ and Tb3+ chelates were investigated. The Eu3+ chelate of the ligand is strongly fluorescent, with a fluorescence quantum yield of 0.156, molar absorption coefficient of 2.95 x 10(4) mol/L/cm at molar absorption maximum of 336 nm, and fluorescence lifetime of 1.29 ms, whereas its Tb3+ chelate is non-fluorescent.

Acids↗

PubMedDate not supplied

Magnetic resonance imaging of acute reperfused myocardial infarction: intraindividual comparison of ECIII-60 and Gd-DTPA in a swine model.

PURPOSE: To compare a necrosis-avid contrast agent (NACA) bis-Gd-DTPA-pamoic acid derivative (ECIII-60) after intracoronary delivery with an extracellular agent Gd-DTPA after intravenous injection on magnetic resonance imaging (MRI) in a swine model of acute reperfused myocardial infarction (MI). METHODS: Eight pigs underwent 90 min of transcatheter coronary balloon occlusion and 60 min of reperfusion. After intravenous injection of Gd-DTPA at a dose of 0.2 mmol/kg, all pigs were scanned with T1-weighted MRI until the delayed enhancement of MI disappeared. Then they were intracoronarily infused with ECIII-60 at 0.0025 mmol/kg and imaged for 5 hr. Signal intensity, infarct-over-normal contrast ratio and relative infarct size were quantified, compared, and correlated with the results of postmortem MRI and triphenyltetrazolium chloride (TTC) histochemical staining. RESULTS: A contrast ratio over 3.0 was induced by both Gd-DTPA and ECIII-60. However, while the delayed enhancement with Gd-DTPA virtually vanished in 1 hr, ECIII-60 at an 80x smaller dose depicted the MI accurately over 5 hr as proven by ex vivo MRI and TTC staining. CONCLUSION: Both Gd-DTPA and ECIII-60 strongly enhanced acute MI. Comparing with fading contrast in a narrow time window with intravenous Gd-DTPA, intracoronary ECIII-60 persistently demarcated the acute MI, indicating a potential method for postprocedural assessment of myocardial viability after coronary interventions.

Animals↗

PubMedDate not supplied

Oxidation of A2E results in the formation of highly reactive aldehydes and ketones.

It has been reported that the photo-oxidation of A2E, a component of human retinal lipofuscin, leads to products that are toxic to cells via dark reactions. Because these compounds have been implicated in the development of various maculopathies such as age-related macular degeneration (AMD), it is important to determine the structures of those deleterious compounds. Both the photo-oxidation and auto-oxidation of A2E lead to the same complex mixture of products, some of which have lower molecular weights than the staring material. Because A2E is homologous to beta-carotene, it was hypothesized that its oxidation would lead to products analogous to those found in oxidized beta-carotene, namely, a series of cleavage products along the acyclic chain with the concomitant formation of aldehydes. This was found to be the case based upon 1) the formation of all of the aldehydes predicted from the oxidation of beta-carotene, 2) the loss of 28 amu (carbonyl moiety) from the molecular ion, 3) the facile reaction of the aldehydes with nitrophenylhydrazines to form nitrophenylhydrazones and 4) the subsequent MS/MS cleavage of those derivatives at the N-N bond. If formed in vivo, these aldehydes would have toxic effects on any cell. Finally, the similarity in product mixtures from both the photo-oxidation and auto-oxidation strongly suggests that the intermolecular photo-oxidation of A2E results primarily from a radical process without the involvement of singlet oxygen. Any formation of singlet oxygen most likely arises from sensitization by the aldehyde oxidation products, as this process is well known for aldehydes, in general, and retinal, specifically.

Aldehydes↗