Biomedical subjects

Zhiliang Li

Publications and source records attributed to Zhiliang Li.

6 recordsLinked to original sources

PubMed2006

QSPR study of polychlorinated diphenyl ethers by molecular electronegativity distance vector (MEDV-4).

Polychlorinated diphenyl ethers (PCDEs) have received more and more concerns as a group of ubiquitous potential persistent organic pollutants (POPs). By using molecular electronegativity distance vector (MEDV-4), multiple linear regression (MLR) models are developed for sub-cooled liquid vapor pressures (P(L)), n-octanol/water partition coefficients (K(OW)) and sub-cooled liquid water solubilities (S(W,L)) of 209 PCDEs and diphenyl ether. The correlation coefficients (R) and the leave-one-out cross-validation (LOO) correlation coefficients (R(CV)) of all the 6-descriptor models for logP(L), logK(OW) and logS(W,L) are more than 0.98. By using stepwise multiple regression (SMR), the descriptors are selected and the resulting models are 5-descriptor model for logP(L), 4-descriptor model for logK(OW), and 6-descriptor model for logS(W,L), respectively. All these models exhibit excellent estimate capabilities for internal sample set and good predictive capabilities for external samples set. The consistency between observed and estimated/predicted values for logP(L) is the best (R=0.996, R(CV)=0.996), followed by logK(OW) (R=0.992, R(CV)=0.992) and logS(W,L) (R=0.983, R(CV)=0.980). By using MEDV-4 descriptors, the QSPR models can be used for prediction and the model predictions can hence extend the current database of experimental values.

Halogenated Diphenyl Ethers↗

PubMed2006

[Promoter recognition using genetic algorithms and neural network].

A new model is developed to recognize eukaryotic promoter sequences from non-promoter sequences based on genetic algorithms and neural network in this paper. Experiment results demonstrate the effectiveness of the system to recognize the promoter sequences on the training set and on the test set. The mean recognition rate is as high as 99% on the training set and 97% on the test set, which shows the algorithms has great prospect application in promoter recognition.

Algorithms↗

PubMed2005

[The effects of pronuciferine on NO and NOS production in cultured human umbilical vein endothelium cells].

OBJECTIVE: To investigate the effects of Pronuciferine on nitric oxide (NO), total nitric oxide synthase (tNOS) and inducible nitric oxide synthase (iNOS) production in cultured Human Umbilical Vein Endothelium Cells (HUVECs). METHODS: Pronuciferine was extracted from plumula nelumbinis. The experiments were performed in HUVECs in vitro. Cell-morphology was observed by light microscope. Cells viability was assessed by MTT assay. NO, tNOS and iNOS were measured by Colorimetry. RESULTS: Cell- morphology and viability weren't affected by Pronuciferine. Pronuciferine significantly increased the level of NO and the activity of tNOS, but had no effect on the activity of iNOS. CONCLUSION: Pronuciferine increases the level of NO by the enhancement of the activity of tNOS. It may have the protection on endothelial function.

Alkaloids↗

PubMed2002

Molecular modeling of quantitative structure retention relationship studies: retention behavior of polychlorinated dibenzofurans on gas chromatographic stationary phases of varying polarity by a novel molecular distance edge vector.

Chemical structures of polychlorinated dibenzodioxin (PCDD) congeners are described by a novel molecular distance edge vector (VMDE), developed in our laboratory, that consists of the modified molecular distance edge parameters based on the identical group as a pseudo-atom instead of a traditional atom. Quantitative structure retention relationships (QSRRs) between the new VMDE parameters and the gas chromatographic retention behavior of PCDDs are then generated by a multiple linear regression method for nonpolar, moderately polar, and polar stationary phases. All QSRR models with a high correlation (R > 0.99) are developed for nonpolar, moderately polar, and polar columns (DB-5, SP-2100, SE-54, and OV-1701). Cross validation with the leave-one-out procedure is performed, and satisfactory results are obtained with high correlation. The obtained results show that the new VMDE vector is adapted to characterize the chemical structure and model the retention behavior of PCDDs on various polar stationary phases.

Journal Article↗

PubMed2002

Pump models assessed by transesophageal echocardiography during cardiopulmonary resuscitation.

OBJECTIVE: Transesophageal echocardiography was performed during closed-chest cardiopulmonary resuscitation (CPR) in in-hospital cardiac arrest to further explore the hemodynamic mechanism of CPR. METHODS: CPR attempts were performed according to advanced cardiovascular life support guidelines in 6 cases of in-hospital cardiac arrest. Multi-plane transesophageal echocardiography was carried out within 15 min of initiation of CPR. Throughout CPR, the motion of the mitral, tricuspid and aortic valves, the changes in the left ventricular cavity size and the thoracic aortic diameter were observed. Trans-mitral and trans-aortic Doppler files of blood flow were also documented. RESULTS: A closure of the mitral and tricuspid valves with simultaneous opening of the aortic valve occurred exclusively during chest compression, resulting in forward blood flow in the pulmonary and systemic circulation. Peak forward aortic flow at a velocity of 58.8 +/- 11.6 cm/s was recorded during the compression phase. Whereas, a closure of the aortic valve and rapid opening of the atrioventricular valves associated with ventricular filling during relaxation of chest compression was noted in all 6 patients. Peak forward mitral flow at a velocity of 60.6 +/- 20.0 cm/s was recorded during the release phase. Mitral regurgitation during the chest compression period was detected in 5 patients, reflecting a positive ventricular-to-atrial pressure gradient. A reduction in the left ventricular chamber and an increase in the thoracic aortic diameter during the compression phase was found in all patients, indicating that direct cardiac compression contributed to forward blood flow. CONCLUSION: These observations favor the cardiac pump theory as the predominant hemodynamic mechanism of forward blood flow during CPR in human beings.

Aged↗

PubMed2002

[The relationship of aldosterone synthase gene polymorphism with hypertension and left ventricular hypertrophy].

OBJECTIVE: To investigate the relationship of gene polymorphism of angiotension converting enzyme (ACE), aldosterone synthase (CYP11B2) with essential hypertension (EH) and left ventricular hypertrophy (LVH) in hypertensive patients. METHODS: (1) Left ventricular mass and geometry were assessed with ECG and echocardiography in 136 hypertensive patients. (2) The insertion/deletion polymorphism of ACE gene and the -344C/T polymorphism of CYP11B2 gene were monitored by polymerase chain reaction (PCR). RESULTS: (1) ACE and CYP11B2 gene showed significant difference in genotype or allele frequency distribution in the group with LVH as compared with the group without (P < 0.05). (2) There was a significant difference in CT + II combined genotype frequency distribution in the group with LVH as compared with the group without (P < 0.05). CONCLUSIONS: (1) No relationship between the polymorphism of CYP11B2 gene and ACE gene with essential hyptension could be found. (2) A significant relationship between the polymorphism of ACE and CYP11B2 gene with LVH in EH could be found. I allele of ACE gene and C allele of CYP11B2 gene may be independent risk factors for LVH in hypertensive patients. (3) There is a synergistic effect between the polymorphism of ACE gene and CYP11B2 gene to result in LVH in EH.

Cytochrome P-450 CYP11B2↗