Biomedical subjects

Z Xie

Publications and source records attributed to Z Xie.

At least 163 records · Page 9Linked to original sources

PubMed1998

Adaptive changes in the capillary network in the left ventricle of rat heart.

Capillaries are nonuniform thin tubes: The arteriolar and venular capillary portions express alkaline phosphatase (AP) and dipeptidyl peptidase IV (DPPIV), respectively. Differences in enzyme activities between arteriolar and venular capillary portions could be shown by staining sections of cardiac tissues for AP and DPPIV after coronary infusion of microspheres and by staining cultured endothelial cells that had been collected from coronary microvessels. Through use of a double staining method for AP and DPPIV, adaptive changes in the capillary network were studied in rat hearts exposed to cold, exercise, hypertension, chronic coronary occlusion, and transient coronary occlusion followed by reperfusion. Two patterns could be seen in the adaptations of the ventricular capillary network. The increase in the venular capillary portions is accompanied by remarkable increases in capillary density and capillary-to-myocyte ratio. The increase in the arteriolar capillary portion seemed to be accompanied by a decrease or only a limited increase in capillary density in stressed hearts. The increase in the total capillary density improves the capacity for oxygen transport to tissues with a high tissue perfusion and a short diffusion distance for oxygen. The increase in the arteriolar capillaries may also improve oxygen transport by increasing the arterial blood perfusing the tissue. This seems, however, a compensation for the limited angiogenesis: The alleviation of stresses, such as pharmacological treatment of the hypertrophied heart and reperfusion after transient ischemia, increases venular capillary portions and capillary density. These changes are discussed with immunohistochemical observations of rapid and prolonged expressions of angiogenic growth factors.

Adaptation, Physiological↗

PubMed1998

[Etiology and clinical analysis of epididymal mass].

The etiology and clinical pathological analysis of 147 cases of epididymal mass were presented. The result showed that the most common mass in inflammatory (66%), and the majority was tuberculosis, the next was cystic diseases (30%). However, neoplasm was relatively less and malignant mass was rare. The diagnosis can be established by careful history, physical examination, and BUS. The selective surgery depends on the nature of diseases, the demand of the patients and the effect of conservative therapy.

Adenomatoid Tumor↗

PubMed1998

[Changes of serum myocardial enzymes in patients with malignant hematologic diseases].

Myocardial enzymes including aspartate aminotransferase (AST), lactate dehydrogenase (LDH), HBD (LDH1 and LDH2), and creatine kinase (CK) and its isoenzyme were monitored in 106 cases of malignant hematologic diseases. The findings were that average values of LDH and HBD increased. There were 82.4% myocardial enzyme levels of 51 patients with leukemia, lymphoma, and myelodysplastic syndrome (MDS) returning to normal or making an obvious reduction after chemotherapy associated with drugs of heart toxicity, while there were increases of the myocardial enzyme levels before chemotherapy. Patients with the increasing of enzyme levels were only 3.9% after chemotherapy. After several courses of chemotherapy, the positive rates of the increasings of CK and CK-MB were higher than that of pretreatment. The results suggest that the injuries of myocardium are possible.

Anthracyclines↗

PubMed1998

[Study on the relationship between DNA topoisomerase II activity and multidrug resistance in leukemic cells].

OBJECTIVE: To explore the relationship between DNA topoisomerase II (Topo II) activity and multidrug resistance in acute leukemia(AL). METHODS: Topo II activities were measured in peripheral blood or bone marrow leukemia cells from 17 pretreated patients and 20 after combination chemotherapy by fluorometric assay. In the same time, multidrug resistant p-glycoprotein expression was detected by immunohistochemistry using JSB-1 monoclonal antibody and mdr-1 gene expression was assayed by RT-PCR in 18 post-chemotherapy patients. RESULTS: Topo II activities were significantly higher in pretreated AL patients (0.6415 +/- 0.0561) than in healthy blood donors (0.2304 +/- 0.0591)(P < 0.005) and significantly lower in post-chemotherapy patients (0.3563 +/- 0.1011) than in pretreated ones (P < 0.005). Among 15 poorly responsed patients, 12 were p170 positive and mdr-1 overexpression, 3 case were p170 negative. Topo II activity was also decreased in these poor responsers. CONCLUSION: Decreased Topo II activity may be another factor in multidrug resistance.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1998

[A clinical observation on the leukopenia treated with shengbaikuai decoction].

OBJECTIVE: To study the effective orally taken medicine in treating the leukopenia. METHODS: Ninety cases of leukopenia induced by chemotherapy were divided into 3 groups. They were test group treated with Shengbaikuai Decoction (SBK), control group and blank group. Their efficacies were compared with each other, 25 cases with nonchemotherapy were also observed. RESULTS: WBC count and absolute neutrophil count (ANC) in test group were higher than those of other groups immediately after treatment and 2 weeks later (P < 0.01). The marked effective rate and total effective rate of test group after 2 weeks were 60.0% and 80.0% (P < 0.001) respectively, which were significantly higher than those of other groups. WBC and ANC count after treatment and 3 weeks later were higher than those before treatment in nonchemotherapy group (P < 0.001). The marked effective rate and total effective rate 3 weeks later were 64.0% and 80.0% respectively. CONCLUSIONS: SBK could increase WBC count rapidly and definitely without apparent side effect.

Adolescent↗

PubMed1998

[Influence of processing methods on alkaloid, toxicity and effect of Strychnos nux-vomica L].

Determination has been made on the contents of strychnine, brucine and ephedrin in different processed products of Strychnos nux-vomica. The acute toxicity, analgesic and antiphlogistic actions of these products have also been detected. The result shows that the product processed with Ephedra sinica can reduce toxicity and promote curative effect. Among the different processing methods the preparation with Ephedra and Liqorice root and the preparation with Ephedra and alcohol appear better and thus useful in practical application.

Animals↗

PubMed1998

[Textual research on herb youba].

A textual research has been conducted to clarify the botanical origin of the herb Youba in ancient medicinal literatures. The name Youba in (Xin Xiu Ben Cao) published in the Tang dynasty and (Ben Cao Gang Mu) published in the Ming dynasty has been confirmed to be the immature tuber of Pinellia pedatisecta (without branches around the tuber), whereas the same name Youba in (Zhi Wu Ming Shi Tu Kao) published in the Qing dynasty refers to Arisaema yunnanense.

China↗

PubMed1998

[The correlation between P-glycoprotein and multidrug resistance of squamous carcinoma in oral and maxillofacial region].

OBJECTIVE: To study the mechanism of drug resistance of oral carcinoma to chemotherapy. METHODS: 40 cases of squamous carcinoma in the oral and maxillofacial region were examined for the multidrug resistance gene product P-glycoprotein using a monoclonal antibody MRK16. RESULTS: P-glycoprotein was detected in 62.5% of the sample. P-glycoprotein expression was related to the chemotherapy and the degree of differentiation. P-glycoprotein expression was higher in post-chemotherapy group than in unchemotherapy group (P < 0.05). Well differentiated tumors expressed P-glycoprotein more frequently (P < 0.05). P-glycoprotein expression was compared with clinic response to chemotherapy. The accuracy rate of prediction is 75%. CONCLUSION: P-glycoprotein plays an important role in mechanism of multidrug resistance of squamous carcinoma in the oral and maxillofacial region.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1998

[Antagonism of the novel cholinolytic tricyclopinate on nicotinic and muscarinic cholinergic receptors].

Tricyclopinate hydrochloride(TCPN.HCl) and methiodide(TCPN.CH3I) have been identified as new chemical entities. The effects of these two compounds on central and peripheral nicotinic and muscarinic cholinergic receptor activities were investigated. Excitation of the central nicotinic receptors by nicotine produced convulsions in mice. The dose-response curves of nicotine for producing convulsions were shifted rightward by TCPN.CH3I in a paralled manner. Excitation of the central muscarinic receptors by arecoline produced tremors in mice. TCPN.HCl was shown to prevent arecoline-induced tremors. In isolated guinea-pig ileum preparations. TCPN.HCl was found to antagonize nicotine-induced contractions due to excitation of ganglionic nicotinic receptors. In xenopus laevis embryo neuron-muscle co-cultured cells, TCPN.HCl blocked spontaneous miniature endplate currents, and showed preference to blocking the nicotinic receptor ion channels, which had a long open time, and high current amplitude. The anticholinergic effects of TCPN.CH3I were weaker than those of TCPN.HCl. In conclusion, TCPN.HCl has potent effects against nicotinic and muscarinic receptors in the central and periphery nervous systems.

Animals↗

PubMed1998

[Study on the pharmacognosy of traditional Chinese medicine tubeimu].

In this article, we have studied the traditional Chinese medicine Tubeimu on the pharmacognosy. This paper reports the thickening condition on the epidermis cell walls of the bulbuls of Tubeimu [Bolbostemma paniculatum (Maxim) Franquet] for the first time and corrects the wrong record in before literature.

Chromatography, Thin Layer↗

PubMed1998

[A kinetic study of organic reaction by Kalman filter and spectrophotometry].

The Kalman filter-spectrometry was used to the study on the chemical dynamics of alpha-Oxo ketene cyclic dithioacetals. Results show that the method can effectively eliminate or reduce the intercomponent interferences in the simultaneous determination of all components. The method was successfully used to study the condensation reaction dynamics of 1-phenyl-2-(1,2-dithioethylene)methylene-1,3-dibutandione and m-nitrophenyl aldehyde.

English Abstract↗

PubMed1997

Drosophila factor 2, an RNA polymerase II transcript release factor, has DNA-dependent ATPase activity.

Drosophila factor 2 has been identified as a component of negative transcription elongation factor (N-TEF) that causes the release of RNA polymerase II transcripts in an ATP-dependent manner (Xie, Z. and Price D. H. (1996) J. Biol. Chem. 271, 11043-11046). We show here that the transcript release activity of factor 2 requires ATP or dATP and that adenosine 5'-O-(thiotriphosphate) (ATPgammaS), adenosine 5'-(beta,gamma-imino)triphosphate (AMP-PNP), or other NTPs do not support the activity. Factor 2 demonstrated a strong DNA-dependent ATPase activity that correlated with its transcript release activity. At 20 microg/ml DNA, the ATPase activity of factor 2 had an apparent Km(ATP) of 28 microM and an estimated Kcat of 140 min-1. Factor 2 caused the release of nascent transcripts associated with elongation complexes generated by RNA polymerase II on a dC-tailed template. Therefore, no other protein cofactors are required for the transcript release activity of factor 2. Using the dC-tailed template assay, it was found that renaturation of the template was required for factor 2 function.

Adenosine Triphosphatases↗

PubMed1997

Enzymatic properties of human Na,K-ATPase alpha1beta3 isozyme.

Recent results of a wide-scale human cDNA sequencing project have identified a cDNA which encodes a hitherto unknown human protein sequence exhibiting structural similarities with beta-subunits of the Na,K- and H,K-ATPase family and with the amphibian Na,KATPase beta3-subunit, in particular. In this study the ability of the putative human beta3-subunit to assemble with the human alpha1-subunit in functionally active Na,KATPase was examined using the baculovirus expression system. The recombinant baculovirus simultaneously expressing both alpha1 and beta3 human proteins was produced using the dual-promoter transfer vector p2Bac. The expression of both human proteins in baculovirus-infected Sf-9 cell membranes detected with specific antibodies resulted in the formation of a catalytically competent alpha1beta3 ATPase complex. Characterization of the recombinant ATPase complex involved the analysis of Na+, K+, and ATP dependencies of enzyme activity and its sensitivity toward ouabain. Preparations of HeLa cell membranes containing alpha1beta1 isozyme of human Na,K-ATPase were used as control. The data obtained clearly demonstrated that alpha1beta3 ATPase exhibits enzymatic properties which are characteristic of Na, K-ATPase. The recombinant alpha1beta3 isozyme displayed significantly lower sensitivity to ouabain than native alpha1beta1. These findings indicate that the hitherto unknown alpha1beta3 isozyme of human Na,K-ATPase is likely to exist in vivo, thus suggesting further expansion of human Na,K-ATPase isozyme diversity. The present studies are the first in which heterologous expression has been used for the characterization of an isozyme of human Na, K-ATPase.

Adenosine Triphosphate↗

PubMed1997

BAG-1 modulates the chaperone activity of Hsp70/Hsc70.

The 70 kDa heat shock family of molecular chaperones is essential to a variety of cellular processes, yet it is unclear how these proteins are regulated in vivo. We present evidence that the protein BAG-1 is a potential modulator of the molecular chaperones, Hsp70 and Hsc70. BAG-1 binds to the ATPase domain of Hsp70 and Hsc70, without requirement for their carboxy-terminal peptide-binding domain, and can be co-immunoprecipitated with Hsp/Hsc70 from cell lysates. Purified BAG-1 and Hsp/Hsc70 efficiently form heteromeric complexes in vitro. BAG-1 inhibits Hsp/Hsc70-mediated in vitro refolding of an unfolded protein substrate, whereas BAG-1 mutants that fail to bind Hsp/Hsc70 do not affect chaperone activity. The binding of BAG-1 to one of its known cellular targets, Bcl-2, in cell lysates was found to be dependent on ATP, consistent with the possible involvement of Hsp/Hsc70 in complex formation. Overexpression of BAG-1 also protected certain cell lines from heat shock-induced cell death. The identification of Hsp/Hsc70 as a partner protein for BAG-1 may explain the diverse interactions observed between BAG-1 and several other proteins, including Raf-1, steroid hormone receptors and certain tyrosine kinase growth factor receptors. The inhibitory effects of BAG-1 on Hsp/Hsc70 chaperone activity suggest that BAG-1 represents a novel type of chaperone regulatory proteins and thus suggest a link between cell signaling, cell death and the stress response.

Adenosine Triphosphatases↗

PubMed1997

Channel formation by antiapoptotic protein Bcl-2.

Bcl-2 is the prototypical member of a large family of apoptosis-regulating proteins, consisting of blockers and promoters of cell death. The three-dimensional structure of a Bcl-2 homologue, Bcl-XL, suggests striking similarity to the pore-forming domains of diphtheria toxin and the bacterial colicins, prompting exploration of whether Bcl-2 is capable of forming pores in lipid membranes. Using chloride efflux from KCl-loaded unilamellar lipid vesicles as an assay, purified recombinant Bcl-2 protein exhibited pore-forming activity with properties similar to those of the bacterial toxins, diphtheria toxin, and colicins, i.e., dependence on low pH and acidic lipid membranes. In contrast, a mutant of Bcl-2 lacking the two core hydrophobic alpha-helices (helices 5 and 6), predicted to be required for membrane insertion and channel formation, produced only nonspecific effects. In planar lipid bilayers, where detection of single channels is possible, Bcl-2 formed discrete ion-conducting, cation-selective channels, whereas the Bcl-2 (Deltah5, 6) mutant did not. The most frequent conductance observed (18 +/- 2 pS in 0.5 M KCl at pH 7.4) is consistent with a four-helix bundle structure arising from Bcl-2 dimers. However, larger channel conductances (41 +/- 2 pS and 90 +/- 10 pS) also were detected with progressively lower occurrence, implying the step-wise formation of larger oligomers of Bcl-2 in membranes. These findings thus provide biophysical evidence that Bcl-2 forms channels in lipid membranes, suggesting a novel function for this antiapoptotic protein.

Bacterial Toxins↗

PubMed1997

Augmentation of ouabain sensitivity of rat liver Na/K-ATPase by in vivo adenovirus-mediated expression of the Na/K-ATPase alpha2 subunit.

These are the first experiments to study the effect of in vivo expression of the Na/K-ATPase alpha2 subunit which serves as a receptor for cardiac glycosides. The alpha2 subunit is not normally expressed in rat liver, so hepatocytes which lack endogenous alpha2 protein are a logical first target to study the effects of alpha2 expression on membrane Na/K-ATPase activity. At 3 days after alpha2 adenovirus vector infusion, Wistar rat livers contained alpha2 DNA, alpha2 mRNA, and alpha2 protein. Rat liver membrane ouabain binding activity and the sensitivity of Na/K-ATPase activity to ouabain significantly increased. Total membrane Na/K-ATPase was regulated at a constant level while expressed alpha2 activity represented 10% of the total active Na/K-ATPase sites in alpha2 transduced rat liver. These studies are the first to establish a paradigm in which an endogenous drug receptor is expressed to alter cellular pharmacologic sensitivity.

Adenoviruses, Human↗

PubMed1997

Isolation and characterization of the human nucleophosmin/B23 (NPM) gene: identification of the YY1 binding site at the 5' enhancer region.

NPM (nucleophosmin/B23) is a major nucleolar protein which is 20 times more abundant in tumor or proliferating cells than in normal resting cells. Recently, it was found that NPM gene is located at the breakpoints of the t(2:5), t(3:5) and t(5:17) chromosome translocation. To understand the human NPM gene's structure and regulation, four genomic clones were isolated from the human chromosome 5 library and their DNA sequences analyzed. The human NPM gene has 12 exons of sizes ranging from 58 to 358 bp. The chromosome breakpoint for t(2:5) and t(5:17) translocation is within intron 4 and the breakpoint for t(3:5) translocation is within intron 6. The initiation site is located 96 bp upstream from the ATG site. A typical TATA box (at -25 nt) and a GC box (at -65 nt) were identified in the promoter region. We identified two gel-shift bands (A and B) with DNA fragment E (-741/-250 nt) by EMSA. A DNA footprint was observed at (-371/-344 nt) with the nuclear extract. A double stranded DNA with the footprint sequence (-371/-344 nt) competed the formation of gel-shift bands A and B in EMSA suggesting that proteins A and B bind to the footprint region. We confirmed that protein A is transcription factor YY1. These results suggest that YY1 may play a role in NPM gene expression. This is the first report on human NPM gene structure and sequence.

Animals↗

PubMed1997

Cloning of the human phospholipase C-gamma1 promoter and identification of a DR6-type vitamin D-responsive element.

The 5'-flanking region of the human phospholipase C-gamma1 gene was isolated from a human P1 genomic DNA library. The S1-nuclease mapping and primer extension analysis revealed that there is a single transcriptional start site located at 135 bases upstream from the translation start codon in the human phospholipase C-gamma1 gene. DNA sequence analysis showed that the sequence around the transcriptional start site is very GC-rich and has no TATA box. The fragment +135 to -877 in the 5'-flanking region of the human phospholipase C-gamma1 gene was subcloned into a luciferase reporter vector. The chimeric gene produced a high level of luciferase activity and responded to 1,25-(OH)2D3 in transiently transfected human keratinocytes. Deletion and mutation studies of the fragment +135 to -877 demonstrated a vitamin D-responsive element that contains a motif arranged as two direct repeats separated by 6 bases (DR6), AGGTCAgaccacTGGACA, located between -786 and -803 base pairs. Incubation of the oligonucleotide containing the DR6 with keratinocyte nuclear extracts produced a specific protein-DNA complex that shifted to a higher molecular weight form upon the addition of an antibody specific to the 1,25-(OH)2D3 receptor. Therefore, the 5'-flanking region of the human phospholipase C-gamma1 gene confers promoter activity and contains a DR6-type vitamin D-responsive element that mediates, at least in part, the enhanced expression of this gene in human keratinocytes by 1, 25-(OH)2D3.

Base Sequence↗