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Biomedical subjects

Q Wu

Publications and source records attributed to Q Wu.

At least 109 records · Page 6Linked to original sources
PubMed2001

[Pulmonary thromboendarterectomy in the management of chronic pulmonary thromboembolic hypertension].

OBJECTIVE: The efficacy of surgical treatment (pulmonary thromboendarterectomy, PTE) in the management of chronic pulmonary thromboembolic hypertension (CTE-PH) was reviewed. METHODS: A retrospective study of 8 patients receiving consecutive PTE in Fuwai cardiovascular hospital was made, with special regard to the operation methods, perioperative management and follow-up. RESULTS: All survived the operation. As compared with preoperative values, all patients presented with significant improvement of systolic pulmonary artery pressure [(39 +/- 15) mmHg versus (101 +/- 24) mm Hg], arterial oxygen tension [(92 +/- 7) mmHg versus (59 +/- 11) mm Hg] and arterial oxygen saturation (0.98 +/- 0.01 versus 0.89 +/- 0.06). Mid-term follow-up showed that the cardiac function of the patients fell into NYHA class I (n = 3) or II (n = 5), with significant improvement in quality of life. CONCLUSION: PTE is effective treatment in the management of CTE-PH.

Adult↗
PubMed2001

[The influence of the change in postburn erythrocyte membrane viscoelasticity on the regional myocardial blood flow].

OBJECTIVE: To explore the characteristics of the dynamic change in postburn erythrocyte membrane viscoelasticity and its influence on the regional myocardial blood flow. METHODS: Wistar rats inflicted with 30% TBSA III degree scalding on the back were employed as the model. The mechanical indices of erythrocytic membrane, such as elastic modulus and the coefficient of viscosity, were determined with micro-pipe sucking methods at preburn and 1, 3, 6, 12, 24 and 48 postburn hours (PBHs). The regional myocardial blood flow was simultaneously monitored with hydrogen clearance methods. RESULTS: The erythrocyte membrane viscoelasticity increased sharply at 3 PBH, reached the peak level at 6 PBH and decreased gradually thereafter to near normal level at 24 PBH. The regional myocardial blood flow decreased obviously at 1 PBH, it reached the lowest level at 6 PBH and bounced back to near normal level at 48 PBHs. The change in the viscoelasticity was significantly and negatively correlated to that of the regional myocardial blood flow. CONCLUSION: The deformability of postburn erythrocyte membrane decreased, leading to the decrease in the regional myocardial blood flow. This might be one of the important reasons of postburn myocardial injury.

Animals↗
PubMed2001

[Management of arterial occlusive diseases of abdominal aorta and iliac artery: experience with 267 cases].

OBJECTIVE: To study the surgical treatment of infrarenal aortic and iliac arterial occlusive disease. METHOD: We analyzed 267 patients with arterial occlusive diseases of the abdominal aorta and iliac artery retrospectively. RESULTS: All the patients were treated by surgery including aortic-iliac bypass in 145 patients, iliac-femoral bypass in 40, femoro-femoral bypass in 45, and axillo-femoral bypass in 37. Their total effective rate and perioperative mortality were 96.5% and 3.5%, respectively. Of the 267 patients, 178 were followed up. The patency rate of prosthesis was 82.0%. CONCLUSIONS: Extra-anatomical bypass is a procedure of choice for high-risk patients, especially for those chronic patients with coronary heart disease, hypertension, cerebral arterial atherosclerosis, and brain infarction.

Adult↗
PubMed2001

[Effect of manganese on the ratio of micronucleus cells in mice marrow].

The ratio of micronucleus in the bone marrow cell of mice induced by manganese (Mn2+, MnCl2) through intraperitoneal injection at doses of 0, 25, 50 and 100 mg/kg respectively was investigated. The number of micronucleus cells per 1000 polychromatic erythrocyte (PCE) from breast bone marrow was counted. The results showed that micronucleus ratio in bone marrow cells were 12.0 and 16.4 per 1000 in the medium and high dosage groups, which were higher than that of control (P < 0.01). There is no distinct difference between the low dosage group and the control group (P > 0.05), but show a rising trend with the dosage of Mn2+. It indicated that the higher the dose of MnCl2, the stronger the toxic effect to the micronucleus in bone marrow cells. MnCl2 is considered having mutation to chromosome and potential heredity toxicity.

Animals↗
PubMed2001

[A possible criteria for diagnosis of early caries in pits and fissures].

OBJECTIVE: The aim of this study was to examine pits and fissures of occlusal surfaces with severe stains by both histological and clinical methods, and to evaluate the criteria for diagnosis of early caries in pits and fissures. METHODS: Thirty-one fresh extracted molars and premolars, severely stained but no detectable defects in the surfaces, walls and floors of occlusal fissures, were collected. The teeth were longitudinally sliced across the stained fissures and ground into sections of 100-140 microns. The sections were observed using microscopy and microradiography. RESULTS: All samples showed early carious lesions in pits and fissures under microscope. Demineralization in walls or floors was identified by microradiography in 30 samples. CONCLUSION: Although without detectable defects, severely stained pits and fissures showed demineralization by using microscopy and microradiography. Thus, early caries in pits and fissures may be identified by the severely stained appearance.

Adolescent↗
PubMed2001

[Cloning and sequence analysis of the phytase phyA gene of Aspergillus niger N25].

The phyA encoding phytase of Aspergillus niger N25 was amplified by the polymerase chain reaction (PCR) with primers designed according to the sequences of the phyA in GenBank. The amplified fragment was cloned and sequenced. The results show that: the coding region is 1506 bp in size, includes a 102 bp intron, and encodes a peptide of 476 amino acid residues, in which there is a signal peptide with 19 amino acids and a mature peptide of 448 amino acids. Comparison of this sequence with the phyA of the natural A. niger NRRL3135 (GenBank Accession: M94550), the most highly secreting-phytase strain, shows that the nucleotide homology is as high as 96.746%, and the amino acid homology comes up to 97.64%. The phyA of A. niger N25 strain in this paper is appropriate to be used to construct the phytase gene-engineering bacteria.

6-Phytase↗
PubMed2001

Comparative experimental study of Ho-Yag laser and true-cut biopsy needle in myocardial revascularization.

OBJECTIVE: To study the mechanism and effects of blood perfusion on acute ischemic region of myocardium through channel created by Ho-Yag laser and True-cut biopsy needles with myocardial contrast echocardiography. METHODS: We partially ligated the left anterior descending coronary artery of canine hearts between the 1st and 2nd diagonal branches to produce two groups of acute myocardial ischemia models and then performed transmyocardial revascularization (TMR) on this region with Ho-Yag laser and True-cut biopsy needles. Myocardial contrast echocardiography was performed with a new generation of ultrasound contrast agent and second harmonic imaging of this region before, during ischemia and after revascularization. Pictures were taken with "R" wave trigger skill. RESULTS: Acoustic density (dB) in the ischemic region (anterior wall) with myocardial contrast echocardiography decreased obviously after the left anterior descending artery was ligated (Laser group: 5, 40 +/- 1.81, Needle group: 7.11 +/- 2.51) compared with that before (Laser group: 11.69 +/- 1.61, Needle group: 12.96 +/- 2.88, P < 0.01). dB increased remarkably after TMR by either laser or True-cut biopsy needle (Laser group: 11.02 +/- 2.01, Needle group: 10.01 +/- 4.45. P < 0.01) compared to that during ischemia and approximated to that before ischemia (P > 0.05). We found that the acoustic density of the contrast developed one picture (one cardiac cycle) ahead in the transmyocardial revascularization region than that in the lateral and other region of the left ventricle wall in the scan of both groups. CONCLUSIONS: Acute ischemic myocardium can be perfused immediately by oxygenated blood from the left ventricle through channels created with both Ho-Yag laser and True-cut biopsy needles. Evidence of blood perfusion through these channels mainly during systolic phase was detected, and myocardial contrast ultrasound using intravenous perfluorocarbon-exposed sonicated dextrose albumin was regarded as a reliable method in the study of transmyocardial revascularization.

Animals↗
PubMed2001

[Simultaneous determination of tryptophan, tyrosine and phenylalanine in injection by derivative fluorescent PLS method].

A new first-derivative fluorescent method by partial least squares (PLS) for the simultaneous determination of tryptophan, tyrosine and Phenylalanine was developed. The determination was carried out in KH2PO4-K2HPO4 buffer solution (pH = 7.4) and at the EX (excite) wavelength of 216.6 nm. The method has been applied to the determination of tryptophan, tyrosine and phenylalanine in compound amino acid injection, and the relative errors are within +/- 7.2%.

Injections↗
PubMed2001

[Two-dimensional infrared correlation spectroscopy on dodecyloxy benzoic acid phase transition].

Thermal spectra of liquid crystal, dodecyloxy benzoic acid were collected over a temperature range of 26-150 degrees C by FTIR microspectroscopy. By taking investigations of temperature-induced changes in dodecyloxy benzoic acid by means of 2D infrared correlation spectroscopy, it was possible to clearly describe the molecular dynamic mechanism of dodecyloxy benzoic acid aggregates in the phase transitions. The analysis shows that p-dodecyloxy benzoic acid crystallized as multi-molecule aggregates through hydrogen bonds between the carboxylic groups, while the long polymethylene residues intermixed each other in solid state. Premelting phenomena in polymethylene residues were observed with temperature up to melting point. It seems that lots of oxy-benzoic acid part recrystallized to cycle dimer as supermolecular liquid crystal during alkyl chain melting in crystal-smectic phase transition. After temperature over 132 degrees C, oxy-benzoic acid part were melted to open dimer and separate molecule in liquid state.

Benzyl Compounds↗
PubMed2001

[Induced tolerance to cardiac allografts with intrathymic injection of donor spleen cells].

OBJECTIVE: To study the methods and mechanisms of immune tolerance in cardiac transplantation. METHODS: Male DA rat hearts were transplanted to male Lewis rats using Ono's model and randomly divided into four groups: untreated (group I), intrathymic injection of 2.5 x 10(7) DA splenocytes to Lewis rat (group II), intraperitoneal injection of 1 ml rabbit anti-rat lymphocyte serum (ALS) to Lewis recipient (group III), intrathymic injection of 2.5 x 10(7) DA splenocytes combined with intraperitoneal injection of 1 ml rabbit anti-rat lymphocyte serum (ALS) to Lewis recipient (group IV). 21 days later heart transplantation was performed. Mean survival time (MST), histological changes and mixed lymphocyte reaction (MLR) were measured after operation. RESULTS: In the group of intrathymic injection of spleen cells combined with ALS treatment, the survival time of heart allografts [MST: (81.8 +/- 7.6)d] was significantly longer than in the groups I [MST: (7.3 +/- 1.0) d], group II [MST:(7.8+/- 1.0)d], and group III [MST(8.2 +/- 1.2) d, P < 0.01]. Only a few inflammatory cells infiltrated in cardiac allografts in group IV. MLR of group IV were significantly decreased compared with those of the normal control (P < 0.01). CONCLUSIONS: The role of thymus as a special site for induction and maintenance of specific immunological unresponsiveness to organ allografts was confirmed. T cell clonal deletion may play an important role in this immune tolerance.

Animals↗
PubMed2000

Dynamic accumulation and degradation of poly(3-hydroxyalkanoate)s in living cells of Azotobacter vinelandii UWD characterized by (13)C NMR.

The synthesis and degradation of poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-hydroxyvalerate) (P(HB-co-HV)) by Azotobacter vinelandii UWD were investigated using natural abundance solution (13)C nuclear magnetic resonance (NMR) in vivo in shake flask culture and in fermenter culture. The synthesis and the degradation of poly(3-hydroxyalkanoate)s (PHA) monomers hydroxybutyrate (HB) and hydroxyvalerate (HV) had different rates. The amount of HB and HV increased dramatically in the initial degradation stage. The results suggest that the intracellular PHA of strain UWD was the subject of dynamic metabolic processing. (13)C NMR in vivo analysis provided a rapid, easy, accurate, non-destructive method to obtain valuable information on the metabolism of PHA.

Azotobacter vinelandii↗
PubMed2000

Mitogen-activated protein kinase p38 mediates regulation of chondrocyte differentiation by parathyroid hormone.

Parathyroid hormone (PTH) and its related peptide regulate endochondral ossification by inhibiting chondrocyte differentiation toward hypertrophy. However, the intracellular pathway for transducing PTH/PTH-related peptide signals in chondrocytes remains unclear. Here, we show that this pathway is mediated by mitogen-activated protein kinase (MAPK) p38. Incubation of hypertrophic chondrocytes with PTH (1-34) induces an inhibition of p38 kinase activity in a time- and dose-dependent manner. Inhibition of protein kinase C prevents PTH-induced p38 MAPK inhibition, whereas inhibition of protein kinase A has no effect. Thus, protein kinase C, but not protein kinase A, is required for the inhibition of p38 MAPK by PTH. Treatment of hypertrophic chondrocytes by PTH or by p38 MAPK inhibitor SB203580 up-regulates Bcl-2, suggesting that Bcl-2 lies downstream of p38 MAPK in the PTH signaling pathway. Inhibition of p38 MAPK in hypertrophic chondrocytes by either PTH, SB303580, or both together leads to a decrease of hypertrophic marker type X collagen mRNA and an increase of the expression of prehypertrophic marker cartilage matrix protein. Therefore, inhibition of p38 converts a hypertrophic cell phenotype to a prehypertrophic one, thereby preventing precocious chondrocyte hypertrophy. Taken together, these data suggest a major role for p38 MAPK in transmitting PTH signals to regulate chondrocyte differentiation.

Animals↗
PubMed2000

Blue-luminescent/electroluminescent Zn(II) compounds of 7-azaindole and N-(2-pyridyl)-7-azaindole: Zn(7-azaindole)2(CH3COO)2, Zn(NPA)(CH3COO)2, and Zn(NPA)((S)-(+)-CH3CH2CH(CH3)COO)2 (NPA = N-(2-pyridyl)-7-azaindole).

A new 7-azaindole zinc(II) compound, Zn(7-azaindole)2(CH3COO)2 (1), a new ligand N-(2-pyridyl)-7-azaindole (NPA), and two NPA zinc(II) complexes, Zn(NPA)(CH3COO)2 (2) and Zn(NPA)((S)-(+)-CH3CH2CH(CH3)COO)2 (3), have been synthesized and structurally characterized. Compound 1 has a tetrahedral geometry, whereas compounds 2 and 3 have irregular six-coordinate geometry. The NPA ligand in compounds 2 and 3 functions as a bidentate chelate to the zinc center. Compound 1 has a blue luminescence in the solution and the solid state. Compounds 2 and 3 emit a blue color in the solid state. In solution, compounds 2 and 3 are fluxional, as established by 1H NMR experiments. Compound 1 is thermally stable, whereas compounds 2 and 3 undergo decomposition when heated in the solid state. A blue electroluminescent device using compound 1 as the emitting layer has been fabricated. Crystal data: NPA, monoclinic, P2(1)/c, a = 13.993(5) A, b = 8.456(3) A, c = 16.886(5) A, beta = 104.666(12) degrees, V = 1932.9(11) A3; 1, triclinic, P1, a = 9.5114(18) A, b = 10.460(7) A, c = 11.002(3) A, alpha = 117.18(3) degrees, beta = 103.287(18) degrees, gamma = 90.94(2) degrees, V = 938.3(7) A3; 2, monoclinic, C2/c, a = 13.234(6) A, b = 9.373(3) A, c = 13.956(7) A, beta = 113.24(3) degrees, V = 1590.7(12) A3; 3, monoclinic, P2(1), a = 11.047(7) A, b = 15.343(9) A, c = 13.785(8) A, beta = 100.123(9) degrees, V = 2300(2) A3.

Journal Article↗
PubMed2000

Corin, a transmembrane cardiac serine protease, acts as a pro-atrial natriuretic peptide-converting enzyme.

Atrial natriuretic peptide (ANP) is a cardiac hormone essential for the regulation of blood pressure. In cardiac myocytes, ANP is synthesized as a precursor, pro-ANP, that is converted to biologically active ANP by an unknown membrane-associated protease. Recently, we cloned a transmembrane serine protease, corin, that is highly expressed in the heart. In this study, we examine effects of corin on pro-ANP processing. Our results show that recombinant human corin converts pro-ANP to ANP and that the cleavage in pro-ANP by corin is highly sequence specific. Our findings suggest that corin is the long-sought pro-ANP-converting enzyme and that the corin-mediated pro-ANP activation may play a role in regulating blood pressure.

Animals↗
PubMed2000

Cloning and mapping of human PKIB and PKIG, and comparison of tissue expression patterns of three members of the protein kinase inhibitor family, including PKIA.

Two novel members of the human cAMP-dependent protein kinase inhibitor (PKI) gene family, PKIB and PKIG, were cloned. The deduced proteins showed 70% and 90% identity with mouse PKIbeta and PKIgamma respectively. Both the already identified pseudosubstrate site and leucine-rich nuclear export signal motifs were defined from the 11 PKIs of different species. The PKIB and PKIG genes were mapped respectively to chromosome 6q21-22.1, using a radiation hybrid GB4 panel, and to chromosome 20q13.12-13.13, using a Stanford G3 panel. Northern-blot analysis of three PKI isoforms, including the PKIA identified previously, revealed significant differences in their expression patterns. PKIB had two transcripts of 1.9 kb and 1.4 kb. The former transcript was abundant in both placenta and brain and the latter was expressed most abundantly in placenta, highly in brain, heart, liver, pancreas, moderately in kidney, skeletal muscle and colon, and very little in the other eight tissues tested. PKIG was widely expressed as a 1.5-kb transcript with the highest level in heart, hardly detectable in thymus and peripheral blood leucocytes and was moderately expressed in the other tissues, with slightly different levels. However, PKIA was specifically expressed as two transcripts of 3.3 kb and 1.5 kb in heart and skeletal muscle. The distinct expression patterns of the three PKIs suggest that their roles in various tissues are probably different.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Intensities of E. coli nucleic acid Raman spectra excited selectively from whole cells with 251-nm light.

Escherichia coli bacteria in the logarithmic growth phase have been investigated by UV resonance Raman spectroscopy. Bacterial whole-cell Raman spectra excited at 251 nm reflect nearly exclusively the nucleic acid composition even though a very large fraction of the bacterial mass is composed of protein. It has been demonstrated that if bacteria are grown under controlled (logarithmic growth) conditions, which give rise to organisms of known average biochemical composition, the intensities of E. coli Raman spectra can be explained quantitatively from the knowledge of component nucleic acid base resonance Raman cross sections.

DNA, Bacterial↗
PubMed2000

Syntheses, structures, and fluxionality of blue luminescent zinc(II) complexes: Zn(2,2',2"-tpa)Cl2, Zn(2,2',2"-tpa)2(O2CCF3)2, and Zn(2,2',3"-tpa)4(O2CCF3)2 (tpa = tripyridylamine).

Three novel Zn(II) complexes containing either 2,2',2"-tripyridylamine (2,2',2"-tpa) or 2,2',3"-tripyridylamine (2,2',3"-tpa) have been synthesized and structurally characterized. Compound 1, Zn(2,2',2"-tpa)Cl2, has a tetrahedral geometry while compounds 2, Zn(2,2',2"-tpa)2(O2CCF3)2, and 3, Zn(2,2',3"-tpa)4(O2CCF3)2, have an octahedral geometry. The 2,2',2"-tpa ligand in 1 and 2 functions as a bidentate ligand, chelating to the zinc center, while the 2,2",3"-tpa ligand in 3 functions as a terminal ligand, binding to the zinc center through the 3-pyridyl nitrogen atom. All three compounds emit a blue color in solution and in the solid state. The emission maxima for the three compounds in solution are at lambda = 422, 426, and 432 nm, respectively. The blue luminescence of the complexes is due to a pi *-->pi transition of the tpa ligand as established by an ab initio calculation on the free ligand 2,2',2"-tpa and complex 1. Compounds 1 and 2 are fluxional in solution owing to an exchange process between the coordinate and noncoordinate 2-pyridyl rings of the 2,2',2"-tpa ligand. Compound 2 is also fluxional owing to a cis-trans isomerization process, as determined by variable-temperature 1H NMR spectroscopic analysis.

Journal Article↗