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Biomedical subjects

Ying Zhou

Publications and source records attributed to Ying Zhou.

63 records · Page 4Linked to original sources
PubMed2002

[Assessment of myocardial ischemia and infarction by intravenous myocardial contrast echocardiography with perfluorocarbon microbubbles]

OBJECTIVE: To assess the value of myocardial contrast echocardiography (MCE) with intermittent second harmonic technique and perfluorocarbon microbubbles in identifying myocardial ischemia and infarction. METHODS: Open-chest dogs were performed by intravenous MCE with perfluorocarbon microbubbles after 3 h of left anterior descending coronary artery (LAD) occlusion. The parameters of time-intensity curve were measured and compared between the normal and ischemic myocardial area at short-axis view of left ventricule midpapillary muscle level. The infarct size assessed by MCE was compared with the gross pathologic specimen stained with triphenyltetrazolium chloride (TTC). RESULTS: The peak intensity (PI), T1/2, and area under curve (AUC) in the ischemic area were significantly different versus the normal area 13.5+/-1.9 compared with 22.5+/-2.4; 16.6+/-0.9 compared with 9.7+/-0.5; 231.6+/-14.9 compared with 405.6+/-12.3 P<0.02). The percents of the no flow area determined by MCE had correlation with those by TTC stain(r=0.89, P=0.01). CONCLUSION: Intermittent second harmonic MCE using intravenous injection of perfluorocarbon microbubbles could assess myocardial perfusion, diagnose ischemia, and define myocardial infarct size.

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

[Cloning of expression vector for VEGF121 and VEGF165 genes encoding human vascular endothelial growth factor].

OBJECTIVE: To clone and construct the expression vector for human vascular endothelial growth factor (VEGF) genes. METHODS: Total RNAs were extracted from human lung tissue of a 4-month-old fetus and subjected to reverse transcriptase-polymerase chain reaction (RT-PCR) with the amplified products cloned into pMD18-T vector. Sequence analysis was performed before the amplified products were cloned into the expression plasmid pcDNA3.1-, the recombinant of which was verified by endonuclease digestion. RESULTS: After RT-PCR using a pair of primers (sense -21/7 bp and antisense 554/576 bp), two bands were identified. The band (487 bp) shorter in length was confirmed as VEGF121 (with the full length of VEGF121 being 444 bp) while the longer band (619 bp) was normal VEGF165 (with the full length of VEGF165 being 576 bp). Interestingly, another slightly longer VEGF165 nucleotide sequence was identified by sequencing analysis, which featured an unique 20 bp insertion precisely between exon 3 and exon 4 from the first ATG of human VEGF165 cDNA. The 20 bp insert was identified as the retaining intron 3 terminal nucleotides containing the splicing signal, which caused frame shift mutation in the reading frame and could probably give rise to a short polypeptides consisting of only 97 amino acid residuals due to the early appearance of stop code UAG in the middle of exon 4. CONCLUSION: We have successfully constructed the expression vector for VEGF121 and VEGF165 genes, and a new possible alternative splicing isoform of VEGF is identified in normal fetus whose molecular mechanism and physiological function needs further investigation.

Cloning, Molecular↗
PubMed2002

[Effect of chronic pressure overload on the left ventricle myocyte apoptosis in rabbits].

OBJECTIVE: To study the effect of chronic pressure overload on the apoptosis of the left ventricle myocytes in rabbits. METHODS: Rabbit models of chronic pressure overload-induced heart failure were prepared in which dynamic changes of apoptotic myocytes in the left ventricle were observed by way of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay. RESULTS: Only a few apoptotic cells was observed in the sham-operated group, while in the experimental group, the apoptotic left ventricle myocytes significantly increased after operation, presenting a peak level between day 3 and day 7. Seven days after the operation, the apoptotic myocytes began to decrease and till day 14, the apoptotic cell number had been smaller than that measured on day 1. When signs of heart failure set in, the apoptotic myocytes were again increased (P<0.001). CONCLUSION: During chronic pressure overload, myocyte apoptosis in the left ventricle is elevated at the early stages and undulates subsequently, with the peak occurring before hypertrophy is obvious.

Animals↗
PubMed2002

[Impact of high response of ovary to gonadotropin stimulation on the outcome of in vitro fertilization and embryo transfer or intracytoplasmic sperm injection].

OBJECTIVE: To evaluate the impact of elevated peak estradiol (E(2)) levels and a high number of retrieved oocytes on implantation and pregnancy rate in patients undergoing in vitro fertilization-embryo transfer (IVF-ET) and intracytoplasmic sperm injection (ICSI). METHODS: Retrospectively analyzed 474 infertile women undergoing 510 cycles for IVF-ET/ICSI treatment during the period of March 1999 to December 2000. Using a standard long protocol/flare-up protocol [(gonadotropic hormone releasing hormone agonist/high pure follicle-stimulating hormone (FSH-HP)/human chorionic gonadotropin (hCG)] for ovarian stimulation. High responders were defined as those who had peak E(2) levels of > 11 010 pmol/L on the day of hCG administration (n = 160) or > 15 retrieved oocytes (n = 148). Normal responders were defined as those who had peak E(2) levels of </= 11 010 pmol/L on the day of hCG administration (n = 350) or </= 15 retrieved oocytes (n = 362). RESULTS: There were statistically significant differences in age, infertile years, basal FSH level and the ampules of FSH-HP required between high and normal responders (P < 0.01 and P < 0.05). Ovarian hyperstimulation syndrome (OHSS) increased significantly in the high responders (P < 0.01). There were no statistically significant differences in implantation rate or pregnancy rate between high and normal responders. CONCLUSION: Elevated peak E(2) levels and high oocytes retrieved were not detrimental to IVF outcome, but had high incidence of OHSS.

Adult↗
PubMed2002

Preparation and characteristics of new coating for solid-phase microextraction.

Poly (methylphenylvinylsiloxane) (PMPVS) coating for solid-phase microextraction (SPME) was first prepared by using sol-gel approach and cross-linking of free radical initiation. The extraction properties of the novel coating for aromatic compounds were investigated using a self-made SPME device coupled with a gas chromatograph-flame ionization detector (GC-FID). The coating provided high surface areas and allowed high extraction efficiency. Compared with some commercial SPME stationary phases, the new phase showed better selectivity and sensitivity toward aromatic compounds. Furthermore, PMPVS coating showed good thermal stability and longer lifetime.

Biphenyl Compounds↗
PubMed2002

[Clinical study of treatment on chronic uric acid nephropathy by integrating Western and traditional Chinese medicine].

OBJECTIVE: To investigate the ameliorative effect on chronic uric acid nephropathy (CUAN) by integrating western and traditional Chinese medicine (IWTCM). METHODS: The 136 CUAN patients were divided into two groups at random, the therapy group of 86 patients were treated by Chinese medicine and allopurinol, and the control group of 50 patients were treated only by allopurinol. The curative effect and the related index such as blood uric acid, renal function, urinary protein, microproteins, blood lipid and hyperviscosity were determined before and after being treated. RESULTS: After three months treatment, the total effective rate in the therapy group (90.7%) was significantly higher (P < 0.01) than that of the control group (56%). The therapy group is also superior to the control group in improving renal function, lipid metabolism and hyperviscosity, decreasing blood uric acid, urinary protein, microproteins in evidence (P < 0.05, P < 0.01). CONCLUSION: IWTCM can obviously improve the ameliorative effect on chronic uric acid nephropathy.

Adult↗
PubMedDate not supplied

Influence of pH and ionic strength on the steric mass-action model parameters around the isoelectric point of protein.

The ion-exchange equilibrium and the dependence of the parameters in the steric mass-action (SMA) model on salt concentration and buffer pH around the isoelectric point of protein were studied. Bovine serum albumin (BSA, isoelectric point = 5.4) was used as a model protein and DEAE Sepharose FF as an ion exchanger. Finite batch adsorption experiments and isocratic elution chromatography were performed for the determination of the model parameters (i.e., characteristic charge, equilibrium constant, and steric factor). The results showed that pH had significant effects on the parameters. With an increase of pH from 4.5 to 6.5, the characteristic charge increased from 0.9 to 3.0 and leveled off as a plateau at pH above 5.5. The charge groups in the contact region of protein surface were considered to play a crucial role on the characteristic charge. The decrease of pH and increase of salt concentration lowered the absolute value of the zeta potential of the protein surface and led to a decrease of the equilibrium constant. The steric factor remained unchanged at about 31 at pH 5.5 and 6.0 and increased to 44.5 at pH 5.0 and 96.8 at pH 4.5, mainly as a result of the lower adsorption capacity of BSA at pH <5.5. Furthermore, the increase of the molecular volume of BSA at pH 4.5 would be an additional reason for the increase of the steric factor. Taking into account the effect of the pH and salt concentration on these parameters, the SMA model described the ion exchange equilibrium of protein more accurately.

Adsorption↗