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Biomedical subjects

Q Wu

Publications and source records attributed to Q Wu.

At least 397 records · Page 22Linked to original sources
PubMed1994

[A seroepidemiological study on sexually transmitted HBV infection].

A seroepidemiological study on HBV infection was conducted among female prostitutes in houses of detention in Guangzhou and Fuzhou in 1989, 1990 to understand the situation of sexually transmitted HBV infection in selected areas of China, and prevalence of HBV infection in sexual misbehavior populations. The incidence of HBV infection was 84.82% among the population, and 21.6% was HBsAg positive. The prevalence of HBsAg was significantly higher in prostitutes than in pregnant women. The results show that there is a relatively serious HBV infection in prostitutes in certain cities along coastal region in China.

Adolescent↗
PubMed1994

Comparison of standard locked-ward treatment versus open-ward rehabilitation treatment for chronic schizophrenic patients. A one-year controlled trial in Canton.

A priority for psychiatric rehabilitation workers in China is to develop less-restrictive methods for managing the estimated 2500 chronically institutionalised patients who are symptomatically stable and have adequate psychosocial functioning but have no family members who are able or willing to take them home. We transferred 45 chronic schizophrenic male in-patients to an open-door rehabilitation ward where they were given as much freedom as possible and encouraged to take part in occupational, social, and recreational activities. The Nurses Observation Scale for Inpatient Evaluation (NOSIE) was used to compare the psychosocial functioning of the 43 patients who completed the year-long trial with that of 43 similar patients who received standard in-patient treatment on a locked ward. Over the year, the experimental group showed a significant improvement in overall functioning, whereas the control group showed no improvement. These findings suggest that open-door rehabilitation wards situated within the hospital can mobilise latent psychosocial functioning and may be a good method for re-introducing chronic schizophrenic patients in China back into the community.

Activities of Daily Living↗
PubMed1994

[Studies on the efficacy of albendazole candy for treatment of intestinal nematode infections].

A single dose of albendazole (candy) 100 mg and 100 mg qd for two days was given respectively to 135 and 321 children who were infected with Enterobius vermicularis. All cases were cured 3wk later according to perianal tape examination. The same drug of 150 mg qd and 200 mg qd for two days was administered respectively to residents with single or multi-infections of Ascaris, hookworm and Trichuris; the egg negative conversion rates of the two dosages were revealed to be 99.4% (466/469) and 99.8% (487/488) for Ascaris infection, 96.8% (91/94) and 94.3% (99/105) for hookworm infection, and 53.4% (228/427) and 76.3% (370/486) for Trichuris infection. The maximal numbers of worm expelled were 100 on d2-3, 88 on d3-5 and 588 on d2-4 for Enterobius, Ascaris and hookworm, respectively; whereas the discharged Trichuris were scarce, merely 4.3 in average. The results exhibited promising efficacy of the drug on Enterobius, Ascaris and hookworm infections, but not so on trichuriasis.

Albendazole↗
PubMed1994

Transfer of human chromosome 3 to an ovarian carcinoma cell line identifies three regions on 3p involved in ovarian cancer.

The molecular pathogenesis of ovarian carcinoma involves altered expression of growth factors, activation of oncogenes and loss of tumor suppressor genes. Loss of heterozygosity on chromosomes 3p, 6q, 11p, 17 and 18q was reported as a significant alteration in ovarian cancer. However, no functional proof has been provided of tumor suppressor activity located in these chromosomal regions. We therefore introduced normal human chromosomes 3 and 11 into an ovarian carcinoma cell line by microcell mediated chromosome transfer. Transfer of chromosome 3 induced senescence and growth arrest as well as suppression of tumorigenicity. Tumors induced by chromosome 3 monochromosomic hybrids consistently lost three small regions on 3p, two of which located in 3p23-24.2 and one located in 3p21.1-21.2, suggesting that these chromosomal regions are important for suppression of tumorigenicity of ovarian carcinoma cells. Transfer of chromosome 11 reduced the in vitro growth properties of ovarian cancer cells but did not significantly affect tumorigenicity. These results provide functional evidence for chromosome 3 tumor suppressor activity in ovarian cancer and define the chromosomal regions on 3p involved in the pathogenesis of this tumor. This experimental system, based on functional effects, may be useful for further delimitation and isolation of critical regions on 3p involved in tumor suppression.

Animals↗
PubMed1993

Synthesis and biological activities of angiotensin II, Sarilesin, and Sarmesin analogues containing Aze or Pip at position 7.

Analogues of [Sar1]angiotensin II, Sarilesin (type I antagonist), and Sarmesin (type II antagonist) with L-azetidine-2-carboxylic acid (Aze) and L-pipecolic acid (Pip) at position 7 have been prepared by the solid-phase method, purified by reverse-phase HPLC, and bioassayed in the rat uterus. Analogues of the superagonist [Sar1]ANGII with Aze or Pip at position 7 and sarcosine (Sar) or aminoisobutyric acid (Aib) at position 1 had high intrinsic activity in the rat isolated uterus assay (34-184%). Analogues of Sarilesin ([Sar1,Ile8]ANGII) with Aze or Pip at position 7 and Sar or Aib at position 1 retained high antagonist activity (pA2 = 7.1-8.3). Analogues of Sarmesin ([Sar1,Tyr-(OMe)4]ANGII) with Aze and Pip at position 7 had pA2 values of 7.4 and 6.5, respectively. [Aze7]-ANGII and [Pip7]ANGII had low activities (12% and 1%, respectively), and deletion of Sar at position 1 of Sarmesin analogues abolished binding (or affinity) as judged from pA2 values. Nuclear Overhauser effect (NOE) spectroscopy studies of [Sar1,Aze7]ANGII in DMSO-d6 have indicated a clustering of the three aromatic rings (Tyr, His, Phe) and proximity of Sar C alpha and Arg C delta protons to the Tyr/Phe ring protons. These data emphasize that replacement of Pro with the lower and higher homologs Aze and Pip does not greatly alter the structural requirements necessary for expression of agonist or antagonist activity, when sarcosine occupies position 1, but not when Asp occupies position 1, suggesting that there is an intimate relationship between the N-terminal and penultimate residues of the molecule in the biologically active conformation of the molecule.

Angiotensin II↗
PubMed1993

Mutagenesis of thrombin selectively modulates inhibition by serpins heparin cofactor II and antithrombin III. Interaction with the anion-binding exosite determines heparin cofactor II specificity.

Thrombin is a multifunctional serine protease that plays a critical role in hemostasis. Thrombin is inhibited by the serpins antithrombin III and heparin cofactor II in a reaction that is dramatically accelerated by glycosaminoglycans. The structural basis of the interaction with these inhibitors was investigated by introducing single amino acid substitutions into the anion-binding exosite (R68E, R70E) and unique insertion loops (K52E, K154A) of thrombin. The rate of inhibition of these recombinant thrombins by antithrombin III and heparin cofactor II was determined in the absence and presence of glycosaminoglycan. The second order rate constant (k2) for inhibition by antithrombin III without heparin was 3.7 x 10(5) M-1 min-1 for wild-type thrombin; rates for the mutant thrombins varied less than 2-fold. For inhibition by antithrombin III with heparin, the rate constant was 4.5 x 10(8) M-1 min-1 for wild-type thrombin with no significant differences between any of the recombinant thrombins. In contrast, the rate constant for inhibition by heparin cofactor II without glycosaminoglycan was 4.3 x 10(4) M-1 min-1 for wild-type thrombin; rates were 10-fold slower for thrombin K52E and 2- to 3-fold slower for thrombins R68E and R70E. The rate constants for inhibition of wild-type thrombin by HCII in the presence of heparin or dermatan sulfate were 9.2 x 10(8) M-1 min-1 and 9.0 x 10(8) M-1 min-1, respectively. Compared to wild-type thrombin, the rate of inhibition by HCII with glycosaminoglycan was 5- to 15-fold slower for thrombins K52E and R70E and 50- to over 100-fold slower for thrombin R68E. Thrombin K154A was inhibited by heparin cofactor II with rates similar to wild-type thrombin in all assays. These results suggest that heparin cofactor II interacts with residue Lys-52 in the proposed S1' subsite and with residues Arg-68 and Arg-70 in the anion-binding exosite of thrombin, and that these interactions contribute to the molecular basis of heparin cofactor II specificity for thrombin.

Antithrombin III↗
PubMed1993

Widespread tissue distribution of aminopeptidase A, an evolutionarily conserved ectoenzyme recognized by the BP-1 antibody.

Early B-lineage cells in mice express a cell surface glycoprotein, recognized by the BP-1 and 6C3 monoclonal antibodies, that has been identified as aminopeptidase A (APA E.C.3.4.11.7). In the present studies we obtained evidence by DNA "zoo-blot" analysis that the APA gene is highly conserved. This ectoenzyme catalyzes the removal of N-terminal Glu- and Asp-residues to convert angiotensin II to angiotensin III, a degradation step important in local regulation of blood pressure in mammals. To gain further insight into the physiology of this molecule, which is shared between immune and vascular systems, we examined the tissue distribution of BP-1 mRNA using a cDNA probe and of the protein antigen using the BP-1 antibody for immunohistology. APA transcripts were present in all tissues examined. Abundant BP-1/APA was found in the intestinal brush border of the small intestine, renal glomeruli, proximal renal tubules, pulmonary alveolar walls and vascular endothelium in many organs. Other tissues containing the BP-1 antigen included stromal cells in the thymus cortex, bile canaliculi in liver, gall bladder epithelium, interlobular ducts in pancreas, the ovarian theca interna, basement membrane of the epididymis and the splanchnopleure in placenta. APA enzyme activities have been identified in most of these locations, in keeping with identification of the BP-1/6C3 antigen as APA. The data suggest this ectopeptidase may serve diverse physiologic roles in a broad spectrum of tissues.

Aminopeptidases↗
PubMed1993

Hyperactive recombination in the mitochondrial DNA of the natural death nuclear mutant of Neurospora crassa.

In Neurospora crassa, a recessive mutant allele of a nuclear gene, nd (natural death), causes rapid degeneration of the mitochondrial DNA, a process that is manifested phenotypically as an accelerated form of senescence in growing and stationary mycelia. To examine the mechanisms that are involved in the degradation of the mitochondrial chromosome, several mitochondrial DNA restriction fragments unique to the natural-death mutant were cloned and characterized through restriction, hybridization, and nucleotide sequence analyses. All of the cloned DNA pieces contained one to four rearrangements that were generated by unequal crossing-over between direct repeats of several different nucleotide sequences that occur in pairs and are dispersed throughout the mitochondrial chromosome of wild-type Neurospora strains. The most abundant repeats, a family of GC-rich sequences that includes the so-called PstI palindromes, were not involved in the generation of deletions in the nd mutant. The implication of these results is that the nd allele hyperactivates a general system for homologous recombination in the mitochondria of N. crassa. Therefore, the nd+ allele either codes for a component of the complex of proteins that catalyzes recombination, and possibly repair and replication, of the mitochondrial chromosome or specifies a regulatory factor that controls the synthesis or activity of at least one enzyme or ancillary factor that is affiliated with mitochondrial DNA metabolism.

Base Sequence↗
PubMed1993

Structure-function relationships of the thrombin-thrombomodulin interaction.

Thrombomodulin is an anticoagulant protein cofactor that modulates the substrate specificity of thrombin and promotes the cleavage of protein C. The structure-function relationships of the thrombin-thrombomodulin interaction have been explored by recombinant DNA and protein chemistry methods. Thrombomodulin binds to thrombin at an anion-binding exosite on the carboxyl-terminal side of the substrate binding cleft. This interaction interferes with the recognition and cleavage of fibrinogen, factor V, and the platelet thrombin receptor. Binding to thrombomodulin also protects thrombin from inhibition by heparin cofactor II. The major thrombin binding site on thrombomodulin consists of EGF-like domains 5 and 6. In addition, EGF-like domain 4 is required for thrombomodulin to accelerate the activation of protein C. Some thrombomodulin molecules contain a chondroitin sulfate moiety attached to a Ser/Thr-rich domain adjacent to the cell membrane. This modification is not required for the cofactor activity of thrombomodulin, but appears to contribute to 'direct anticoagulant' activity--the ability of thrombomodulin to inhibit fibrinogen clotting, factor V activation, and platelet activation. The chondroitin sulfate moiety of thrombomodulin also can affect the rate of thrombin inhibition by antithrombin III, possibly by competing with heparin for the heparin binding site on thrombin. Detailed understanding of these interactions could lead to new strategies for the treatment of bleeding or thrombotic disorders.

Amino Acid Sequence↗
PubMed1993

[Effects of stimulation of SmI and electroacupuncture on nociceptive responses of the ventrobasal complex].

In order to confirm the idea that the cerebral cortex is involved in acupuncture analgesia through descending modulation, the effects of stimulation of SmI and electroacupuncture on nociceptive responses of VB neurons were investigated. The experiments were carried out on lightly anesthetized rats. Single unit activities of VB neurons were extracellularly recorded with glass microelectrodes. The results showed that both electrical stimulation of SmI (n = 11) and electroacupuncture at left. "Huantiao" (G30) point (n = 11) could inhibit the nociceptive responses of VB neurons and their effects were similar. These results suggested that SmI may play a role in acupuncture analgesia through corticofugal modulation on VB.

Animals↗
PubMed1993

[Study on antibacterial proteins from rabbit bladder mucosa].

Acid-soluble extract of rabbit bladder mucosa was obtained by washing out the bladder of normal female New Zealand rabbit with 1% acetic acid in the presence of proteinase inhibitors. Acid urea polyacrylamide electrophoresis (AU-PAGE) analysis indicated that the extract had more than 10 main protein bands. The currently-known antibiotic peptides, e. g. lysozyme and defensin-like molecules were not found in this material. When tested for antibacterial activity by using ultrasensitive radial diffusion assay, the acid-soluble extract effectively killed E. coli ML-35P. The gel overlay assay showed that the anti-bacterial activity of the acid-soluble extract was relevant to two protein bands referred to as rabbit bladder protein 1 (Rab BP-1) and rabbit bladder protein 2 (Rab BP-2). The Rab BP-1 and Rab BP-2 accounted for 2.5% and 1.2% of the total acid-soluble extract proteins, respectively. These results suggest that the long recognized ability of the normal rabbit bladder wall to kill adherent E. coli may result from the presence of endogenous antibacterial proteins associated with its mucosa.

Animals↗
PubMed1993

[The physical properties, pharmacology and antifertility action of crystal trichosanthin protein liposome].

The crystal trichosanthin protein liposome (TPL) was prepared by an emulsion-forming method. The rate of entrapment was 33.0-44.8% and the rate of recovery was 95.15-99.58%. The determination of trichosanthin protein was accomplished by spectrophotometry at 650 nm, thus eliminating completely the interference of lipids. The distribution of particle size of TPL was mainly in the range of 1-2 microns (96.9%). TPL was sterilized by 60Co radiation at 4 degrees C for 90 min and was stable when stored at 4 degrees C, 25 degrees C and 37 degrees C. The seepage rate of trichosanthin from the liposome was 15.22% after storage for 38 days at room temperature. Experiments showed that TPL had a slight allergic reaction, but was safe by hemolysis and coagulation tests. When the mice were given TPL ip 8 micrograms per animal 6 days after pregnancy, the rate of termination of early pregnancy was 83.3%. It thus appears that TPL can terminate early pregnancy in mice distinctly. This indicates that TPL may be expected to be developed into a new type of anti-early pregnancy preparation.

Abortion, Induced↗
PubMed1993

Effects of rhynchophylline on motor activity of mice and serotonin and dopamine in rat brain.

Rhynchophylline (Rhy) reduced the spontaneous motor activity and enhanced the sedative and hypnotic effects of sodium pentobarbital in mice. The effects of Rhy on serotonin (5-HT) and dopamine (DA) concentrations in rat brain, and the release of 5-HT and DA from the regional brain slices were studied by a fluorescence detector. Rhy increased the 5-HT content in the hypothalamus and cortex, but reduced the DA concentrations in the cortex, amygdala, and spinal cord. Rhy promoted the release of endogenous DA from 4 brain regions. The release of 5-HT was increased in 2 brain regions and decreased in hypothalamus slice. However, Rhy inhibited the release of both 5-HT and DA evoked by high potassium.

Alkaloids↗
PubMed1992

Localization of the single-stranded DNA binding site in the thrombin anion-binding exosite.

Single-stranded DNA molecules containing a 15-nucleotide consensus sequence have been reported to inhibit thrombin activity. The mechanism of the inhibition was studied using a consensus 15-mer oligonucleotide and two recombinant mutant thrombins: the anion-binding exosite mutant thrombin R70E, and thrombin K154A, in which the mutation was located in a surface loop outside of the exosite. The consensus 15-mer oligonucleotide inhibited both fibrinogen-clotting and platelet-activation activities of plasma-derived thrombin, recombinant wild type thrombin, and mutant thrombin K154A in a sequence-specific and dose-dependent manner, whereas it did not inhibit either activity of mutant thrombin R70E. The 15-mer oligonucleotide also inhibited thrombomodulin-dependent protein C activation by plasma-derived thrombin. In competition equilibrium binding experiments, binding of 125I-labeled diisopropyl phosphoryl-thrombin to thrombomodulin was completely inhibited by the consensus 15-mer oligonucleotide with a Kd value of 2.68 +/- 0.16 nM. These results suggest that Arg-70 in the anion-binding exosite of thrombin is a key determinant for interaction with specific single-stranded DNA molecules, and that binding of single-stranded DNA molecules to the exosite prevents the interaction of thrombin with fibrinogen, the platelet thrombin receptor, and thrombomodulin.

Base Sequence↗
PubMed1992

Effects of ligands on reduction of oxygen by vanadium(IV) and vanadium(III).

V(IV) and V(III) reduce molecular oxygen with increasing rates as the pH is raised from 6.0 to 7.4. Under all conditions tested, V(IV) is the more efficient reductant. EDTA and ATP generally inhibit the reduction of oxygen by V(III) and V(IV). In contrast, desferrioxamine accelerates the reduction of oxygen by V(IV) but with decreasing effectiveness at pH 7.4 compared to pH 6.0, while desferrioxamine accelerates the reduction of oxygen by V(III) only at pH 6.0. Histidine enhances the reduction of oxygen by V(IV) at pH 7.0 and 7.4. The observed rates of oxygen reduction by V(III) and V(IV) imply that the intracellular distribution of vanadium among its redox states reflects not an equilibrium but a steady state.

Adenosine Triphosphate↗
PubMed1992

Ligand specificity of human thrombomodulin. Equilibrium binding of human thrombin, meizothrombin, and factor Xa to recombinant thrombomodulin.

Thrombomodulin is an endothelial glycoprotein that serves as a cofactor for protein C activation. To examine the ligand specificity of human thrombomodulin, we performed equilibrium binding assays with human thrombin, thrombin S205A (wherein the active site serine is replaced by alanine), meizothrombin S205A, and human factor Xa. In competition binding assays with CV-1(18A) cells expressing cell surface recombinant human thrombomodulin, recombinant wild type thrombin and thrombin S205A inhibited 125I-diisopropyl fluorophosphate-thrombin binding with similar affinity (Kd = 6.4 +/- 0.5 and 5.3 +/- 0.3 nM, respectively). However, no binding inhibition was detected for meizothrombin S205A or human factor Xa (Kd greater than 500 nM). In direct binding assays, 125I-labeled plasma thrombin and thrombin S205A bound to thrombomodulin with Kd values of 4.0 +/- 1.9 and 6.9 +/- 1.2 nM, respectively. 125I-Labeled meizothrombin S205A and human factor Xa did not bind to thrombomodulin (Kd greater than 500 nM). We also compared the ability of thrombin and factor Xa to activate human recombinant protein C. The activation of recombinant protein C by thrombin was greatly enhanced in the presence of thrombomodulin, whereas no significant activation by factor Xa was detected with or without thrombomodulin. Similar results were obtained with thrombin and factor Xa when human umbilical vein endothelial cells were used as the source of thrombomodulin. These results suggest that human meizothrombin and factor Xa are unlikely to be important thrombomodulin-dependent protein C activators and that thrombin is the physiological ligand for human endothelial cell thrombomodulin.

Cells, Cultured↗