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Biomedical subjects

Qin Wang

Publications and source records attributed to Qin Wang.

At least 127 records · Page 7Linked to original sources
PubMed2003

[Comparing study on oviposition preference and host-selecting behavior of larvae of rice and water-oat population or rice stem borer, Chilo suppressulis].

The oviposition preference of female of rice and water-oat population of rice stem borer was studied in the oviposition cage (1 m x 1 m x 0.8 m) in laboratory. The results showed that there was no significant difference between the numbers and distributions of eggs laid by the two populations, but each population preferred to lay its non-hatching ovum on the non-host plant. The host-selection behavior of larvae of two host populations was also investigated by Y-tube olfactory. When the leaf or leaf shell of rice and water-oat was provided to larvae of rice population in choice test, 4th and 6th instar larvae of rice population preferred rice leaf to water-oat leaf and 2nd and 4th instar larvae preferred leaf shell of rice to leaf shell of water-oat. When leaves of rice and water-oat were provided to larvae of water-oat population in choice test, except for 1st instar, each stadium of larvae preferred water-oat leaf to rice leaf, and when leaf shells of rice and water-oat were provided, all stadiums of larvae preferred leaf shell of water-oat to leaf shell of rice. These results demonstrated that intraspecies differentiation between the two populations, and the specialization of water-oat population of rice stem borer to host was higher than that of rice population.

Animals↗
PubMed2002

Regulated interactions of the alpha 2A adrenergic receptor with spinophilin, 14-3-3zeta, and arrestin 3.

The present studies demonstrate that no single stretch of sequence in the third intracellular (3i) loop of the alpha(2A) adrenergic receptor (alpha(2A)-AR) can fully account for its previously described interactions with spinophilin (Richman, J. G., Brady, A. E., Wang, Q., Hensel, J. L., Colbran, R. J., and Limbird, L. E. (2001) J. Biol. Chem. 276, 15003-15008), 14-3-3zeta (Prezeau, L., Richman, J. G., Edwards, S. W., and Limbird, L. E. (1999) J. Biol. Chem. 274, 13462-13469), and arrestin 3 (Wu, G., Krupnick, J. G., Benovic, J. L., and Lanier, S. M. (1997) J. Biol. Chem. 272, 17836-17842), suggesting that a three-dimensional surface, rather than a linear sequence, provides the basis for these interactions as proposed for 3i loop tethering of the alpha(2A)-AR to the basolateral surface of Madin-Darby canine kidney cells (Edwards, S. W., and Limbird, L. E. (1999) J. Biol. Chem. 274, 16331-16336). Sequences at the extreme N-terminal and C-terminal ends of the 3i loop are critical for interaction with spinophilin but not for interaction with 14-3-3zeta or arrestin 3, for which the C-terminal half of the loop is more important. Competition binding for (35)S-labeled alpha(2A)-AR 3i loop binding to glutathione S-transferase (GST)-spinophilin amino acids 151-444 revealed a relative affinity of spinophilin congruent with arrestin > 14-3-3zeta for the unphosphorylated alpha(2A)-AR 3i loop. Agonist occupancy of the alpha(2A)-AR increases receptor association with spinophilin, and arrestin 3 appears to compete for this enrichment. However, when the G protein-coupled receptor kinase 2 substrate sequence was deleted from the 3i loop, arrestin 3 could not compete for the agonist-enriched binding of spinophilin to the mutant alpha(2A)-AR. These data are consistent with a model where sequential or competitive interactions among spinophilin, arrestin, and/or 14-3-3zeta play a role in alpha(2A)-AR functions.

Amino Acid Substitution↗
PubMed2002

Lung microvascular and arterial endothelial cells differ in their responses to intercellular adhesion molecule-1 ligation.

Neutrophil adherence to tumor necrosis factor-alpha (TNF-alpha)-treated human pulmonary microvascular endothelial cells (PMECs) induces cytoskeletal changes in endothelial cells that require intercellular adhesion molecule-1 (ICAM-1)-dependent signaling events. This study determined whether similar changes occurred in rat PMECs and whether rat pulmonary arterial endothelial cells (PAECs) responded differently. Neutrophil adherence induced an increase in the formation of F-actin and in the apparent stiffness of TNF-alpha-treated rat PMECs. These responses, however, were absent in PAECs. To determine the mechanisms underlying these differences, ICAM-1-mediated signaling events were compared. Upregulation of ICAM-1 by TNF-alpha and redistribution of ICAM-1 induced by cross-linking antibodies were similar in both cell types. However, neutrophil adherence induced production of reactive oxygen species only in PMECs and not in PAECs. Moreover, phosphorylation of p38 mitogen-activated protein kinase induced by ICAM-1 cross-linking occurred only in PMECs and not in PAECs. This increase in p38 phosphorylation in PMECs was inhibited by allopurinol, a xanthine oxidase inhibitor. These data demonstrated that whereas TNF-alpha upregulated ICAM-1 and ICAM-1 cross-linking induced a similar redistribution of ICAM-1 on the endothelial cell surface, ICAM-1 ligation initiated p38 activation and cytoskeletal rearrangements only in PMECs and not in PAECs. Thus, neutrophil adhesion through ICAM-1 induced signaling events leading to cytoskeletal changes only in PMECs, the site of neutrophil emigration and edema formation, and not in PAECs.

Actins↗
PubMed2002

Receptor-selective effects of endogenous RGS3 and RGS5 to regulate mitogen-activated protein kinase activation in rat vascular smooth muscle cells.

Regulators of G protein signaling (RGS) proteins compose a highly diverse protein family best known for inhibition of G protein signaling by enhancing GTP hydrolysis by Galpha subunits. Little is known about the function of endogenous RGS proteins. In this study, we used synthetic ribozymes targeted to RGS2, RGS3, RGS5, and RGS7 to assess their function. After demonstrating the specificity of in vitro cleavage by the RGS ribozymes, rat aorta smooth muscle cells were used for transient transfection with the RGS-specific ribozymes. RGS3 and RGS5 ribozymes differentially enhanced carbachol- and angiotensin II-induced MAP kinase activity, respectively, whereas RGS2 and RGS7 ribozymes had no effect. This enhancement was pertussis toxin-insensitive. Thus RGS3 is a negative modulator of muscarinic m3 receptor signaling, and RGS5 is a negative modulator of angiotensin AT1a receptor signaling through G(q/11). Also, RGS5 ribozyme enhanced angiotensin-stimulated inositol phosphate release. These results indicate the feasibility of using the ribozyme technology to determine the functional role of endogenous RGS proteins in signaling pathways and to define novel receptor-selective roles of endogenous RGS3 and RGS5 in modulating MAP kinase responses to either carbachol or angiotensin.

Animals↗
PubMed2002

Tetra-arsenic tetra-sulfide for the treatment of acute promyelocytic leukemia: a pilot report.

In the past 6 years, we treated 129 patients who had acute promyelocytic leukemia (APL) with a new arsenic agent, oral tetra-arsenic tetra-sulfide (As(4)S(4)). Nineteen of the patients had newly diagnosed APL, 7 had first relapse, and 103 had hematologic complete remission (HCR). HCR was achieved in all patients with newly diagnosed APL and in all those with hematologic relapse. Of 16 patients with newly diagnosed disease and available cytogenetic and molecular analyses, 14 had cytogenetic and molecular complete remission (CR). Cytogenetic and molecular CR was also obtained in 5 of the 7 patients with hematologic relapse. In the HCR group, 35 of 44 patients positive for PML-RARalpha at baseline became negative. In the newly diagnosed group, estimated disease-free survival (DFS) rates for 1 and 3 years were 86.1% and 76.6%, respectively, with a median follow-up time of 13.5 months (range, 2-40 months). In the HCR group, DFS rates for 1 and 6 years were 96.7% and 87.4%, respectively, with a median follow-up of 23 months (range, 2-71 months). Treatment with As(4)S(4) was well tolerated, with only moderate side effects, including asymptomatic prolongation of corrected QT interval, transient elevation in liver enzyme levels, rash, and mild gastrointestinal discomfort; neither myelosuppression nor appreciable long-term side effects occurred. Degeneration or apoptosis of APL promyelocytes was observed during As(4)S(4) therapy. Pharmacokinetic studies showed that the agent was absorbed rapidly. Most urinary arsenic excretion occurred within the first 24 hours. Both blood and urinary arsenic levels declined after discontinuation of As(4)S(4). Our results show, for the first time, that As(4)S(4) treatment alone is highly effective and safe in both remission induction and maintenance therapy in patients with APL, regardless of disease stage.

Adolescent↗
PubMed2002

Analysis of stromal-epithelial interactions in prostate cancer identifies PTPCAAX2 as a potential oncogene.

A PCR-based subtractive hybridisation technique was used to identify genes involved in stromal-epithelial interactions in prostate cancer. Eight genes were identified as being differentially expressed in benign prostatic fibroblast cells after stimulation with tumourigenic LNCaP conditioned media. One of these genes, protein tyrosine phosphatase CAAX2 (PTPCAAX2; also described as PTP4A and OV-1), has recently been shown to be oncogenic in hamster pancreatic epithelial cells. We show that PTPCAAX2 expression is up-regulated 4-fold in benign prostatic fibroblast cells 24 h after stimulation with LNCaP conditioned media and up-regulated 9-fold in prostatic tumour fibroblast cells. PTPCAAX2 overexpression was also detected in both androgen-dependent and androgen-independent prostate cancer cell lines and prostate tumour tissue, as determined by RT-PCR analysis and in situ hybridisation. These observations of PTPCAAX2 overexpression in prostate tumour cells and tissue suggest that PTPCAAX2 may potentially function as an oncogene in prostate cancer.

Adult↗
PubMed2002

A novel TCTG(G/C) direct repeat and an A/T-rich HMG2-binding site control the expression of the rat cardiac troponin T gene.

We previously showed that the rat cardiac troponin T proximal promoter (-497bp from the transcriptional start site) was sufficient to confer cardiac-specific expression of a reporter gene in both cultured cardiomyocytes and transgenic mice. This promoter consists of two cis-regulatory modules with high sequence similarity. Nucleotides from -319 to -289 (termed D2) and nucleotides from -249 to -209 (termed F41) contain a TCTG(G/C) direct repeat and an A/T-rich sequence. Competition gel mobility shift assays revealed that the same protein factors were bound to both D2 and F41. Deletion and religation studies of the promoter suggested that D2 acted as an enhancer but could not totally substitute for the F41 function. Mutational analyses demonstrated that the direct repeat was required for the DNA-binding and promoter activity. Moreover, cardiac-specific 42kDa proteins and a ubiquitous high mobility group 2 (HMG2) protein were identified to be responsible for the binding to the TCTG(G/C) direct repeat and the A/T-rich sequence, respectively. Overexpression of HMG2 had differential effects on the promoter in cardiomyocytes versus fibroblasts. Our results provided the first evidence to support that HMG2 together with tissue-specific factors could direct a stimulatory or inhibitory effect on thecardiac troponin T gene expression in heart or non-heart tissue, respectively.

AT Rich Sequence↗
PubMed2002

Current study of APL treatment in China.

Natural As4S4 and As2S3 are major components in realgar and orpiment, which also contain small amount of As2O3 and other toxic materials. Liu YF showed with us that NB4 cell line and its mice model were more sensitive to As4S4 than to As2O3 and As2S3. That was in agreement with the clinical data available from China. Wang FR and we proved in mice and in clinical pharmaceutical study that ground Seman platycladi as an excipient can appreciably increase the blood level of arsenic when taken P.O. together with As4S4. Our clinical study with 130 patients with t(15;17) APL showed both As4S4 and As2S3 alone were very effective in CR induction, including cytogenetic remission and PML-RAR reversion, yet the relapse rate was higher in the group treated by As4S4 alone than in the group treated together with other autileukemic agents, either together or in sequence. In the later group, LFS for 1 and 6 years was 96.7% and 87.4%, and the over-all survival for 1 and 6 years was 98.9% and 93.9%. High dose chemotherapy was proven to be not only unsafe but also unnecessary. In newly diagnosed APL patients with neutropenia, CR could be safely achieved by As4S4 P.O. and/with ATRA. Chemotherapy was then followed. In patients with leukocytosis, chemotherapeutic agents such as hydroxyurea or harringtonine was added at the beginning and then followed by anthracycline and asparaginase. The reasons of APL relapse after patients receiving As4S4 P.O. were: 1: emergence of a resistant cell clone showing additional chromosomal abnormalities other than t(15;17); 2: decrease of blood As level. The resistant APL case could respond favorably to combination of As4S4 P.O. together with ATRA. The blood level of As could be raised by modification of the preparation under investigation. Allogeneic stem cell transplantation (allo-SCT) is the last option in relapsed patients, became autologous stem cell transplantation (ASCT) has a significantly better outcome. In a few hospitals ASCT was performed early in the CR1. In rare cares, patients were referred with intra-cranial hemorrhage. CT or EMR scan was done urgently at this instance. Cranial surgery carried out without a minute of delay resulted in the rescue and long survival of patient, while delay of surgery had resulted in irreversible damage of Pons/Medulla oblongata and ended in death. As2O3 IV had been used with success in mentally unclear patients not suffering from intra-cranial hemorrhage. Although no parallel clinical trial has been done to compare the efficacy of As2O3 and As4S4, yet the fact was it was easier for doctors and patients to carry out and receive maintenance treatment with oral As4S4 rather than with As2O3. According to the data and principles above, most of the t(15;17) APL patients can be cured.

Animals↗
PubMed2002

CD44 deficiency leads to enhanced neutrophil migration and lung injury in Escherichia coli pneumonia in mice.

CD44 is a major cell-surface receptor for hyaluronic acid (HA), a glycosaminoglycan component of extracellular matrix. HA-CD44 interactions have been implicated in leukocyte extravasation into an inflammatory site. This study examined the role of CD44 in acute inflammatory responses during pneumonias induced by Escherichia coli and Streptococcus pneumoniae using CD44-deficient mice. In E. coli-induced pneumonia, neutrophil accumulation in the lungs and edema formation was increased by 84% and 88%, respectively, in CD44-deficient mice compared to wild-type mice. In contrast, no difference was observed between these genotypes in S. pneumoniae-induced pneumonia, and the HA content in the lungs decreased after instillation of S. pneumoniae, but not E. coli, in both genotypes. Studies to determine the mechanisms for this enhanced response showed that: 1) neutrophil apoptosis was not different between these two genotypes in either type of pneumonia; 2) CD44 deficiency resulted in enhanced mRNA expression of several inflammatory genes; and 3) CD44-deficient neutrophils migrated through Matrigel in response to chemoattractants faster and in greater numbers than wild-type neutrophils in vitro and this increase was in part dependent on HA content in the Matrigel. These data demonstrate that CD44 deficiency results in enhanced inflammation in E. coli but not S. pneumoniae-induced pneumonia, suggesting a previously unrecognized role for CD44 in limiting the inflammatory response to E. coli.

Animals↗
PubMed2002

Ribozyme-mediated suppression of G protein gamma subunits.

Efforts to determine the sequence of the human genome have resulted in sequence information on thousand of genes. Now, the challenge is to determine the functions of this myriad of genes, including those encoding the G protein subunit families. In this chapter, we describe the successful use of ribozymes to inactivate mRNAs expressed from the G protein gamma subunit genes. Ribozymes are unique in that they can inactivate specific gene expression, and thereby can be used to help identify the function of a protein or the role of a gene in a functional cascade. Compared to other means of identifying the role of a gene (i.e., transgenic or knockout animals), ribozymes are specific and relatively easy to use. Moreover, ribozymes are able to discriminate closely related, or even mutated, sequences within gene families. Thus, in addition to elucidating functions, ribozymes have the potential to be used in treating genetic disorders associated with mutations of G protein subunits.

Base Sequence↗
PubMed2002

The signaling pathways induced by neutrophil-endothelial cell adhesion.

Adhesion of neutrophils to vascular endothelial cells (ECs), mediated by the interaction of CD11/CD18 and intercellular adhesion molecule-1 (ICAM-1), is often required for neutrophil transmigration across endothelium during most inflammatory responses. Induction of intracellular signaling in neutrophils as a result of adhesion has been recognized for many years. Recent studies demonstrated that neutrophil-endothelial adhesion also activates ECs. Examples of neutrophil adherence-induced changes in ECs include increases in intracellular Ca(2+), production of reactive oxygen species, and actin cytoskeleton changes. These changes result, in part, from ligation of EC adhesion molecules. This review article focuses on the signaling events that occur in ECs during neutrophil adhesion and the role of EC adhesion molecules, particularly ICAM-1, in the initiation of these signaling events in ECs. The evidence to date describing the molecular basis of ICAM-1-induced signaling will be summarized. Finally, the potential physiological roles of these signaling events induced by EC adhesion molecules in mediating neutrophil migration will be addressed.

CD11 Antigens↗
PubMed2002

Serum xanthine oxidase: origin, regulation, and contribution to control of trypanosome parasitemia.

African trypanosomiasis is caused by Salivarian trypanosomes, tsetse fly-transmitted protozoa that inhabit the blood plasma, lymph and interstitial fluids, and, in the case of Trypanosoma brucei species, also the cerebrospinal fluid of mammal hosts. Trypanosomiasis in people and domestic animals manifests as recurring waves of parasites in the blood and is typically fatal. In contrast, trypanosomiasis in Cape buffaloes, which are naturally selected to resist the disease, is characterized by the development of only one or a few waves of parasitemia, after which the infection becomes cryptic, being maintained by the presence of 1-20 mammal-infective organisms/ml of blood. The control of the acute phase of parasitemia in Cape buffaloes correlates with a decline in blood catalase activity and the generation of trypanocidal H(2)O(2) in serum during the catabolism of endogenous purine by xanthine oxidase. Here we review features of this response, and of trypanosome metabolism, that facilitate H(2)O(2)-mediated killing of the parasites with minimal damage to the host. We also discuss the origin and regulation of serum xanthine oxidase and catalase, and show how recovery of serum catalase in infected Cape buffaloes precludes a role for H(2)O(2) in the long-term, stable suppression of trypanosome parasitemia.

Amino Acid Sequence↗
PubMed2002

[Effect of sodium chloride treatment on remineralization of human root dentine caries in vitro].

OBJECTIVE: To investigate the influence of soluble phosphoprotein removal from artificial dentin caries lesions by pretreatment of NaCl on subsequent remineralization. METHODS: Human root dentin samples were demineralized in an acidic gel (pH = 4.4) at 37 degrees C for 48 hours. Samples were pretreated with 0.5 mol/L NaCl solution and 0.5 mol/L disodium EDTA solution respectively. The histomorphologic changes of root caries surface were examined by scannings electronic microscope. Mineral profiles were assessed by means of microradiography. RESULTS: No histomorphologic changes were present on root caries surface after treated with 0.5 mol/L NaCl solution, while many opened dentin tubules were seen after treated with 0.5 mol/L disodium EDTA solution. The remineralization results showed that pretreatment with 0.5 mol/L NaCl solution increased more remineralization than pretreated with 0.5 mol/L disodium EDTA solution. CONCLUSION: 0.5 mol/L NaCl solution has no damage on the root caries surface. The in vitro results suggested that removal of soluble phosphoprotein from dentin lesions is an interesting approach to enhance remineralization.

Dental Caries↗
PubMed2002

[Results of bronchoplasty by fiberoptic bronchoscopic balloon dilatation in the management of proximal benign tracheobronchial stenosis].

OBJECTIVE: To assess the effect and safety of balloon dilatation through fiberoptic bronchoscopy in the management of benign tracheobronchial stenosis. METHODS: Thirty-seven patients with proximal benign tracheobronchial stenosis were treated by balloon dilatation through flexible fiberoptic bronchoscopy. A fiberoptic bronchoscope was inserted, a balloon catheter was sent to the stenotic segment from the working channel and positioned in the stenotic bronchus. Under direct visualization, the balloon was inflated for 1 min to 3 min. Repeat inflation-deflation cycles were done if airway narrowing remained after the initial operation. Before the procedure and immediately after the last operation, airway diameters, dyspnea index and complications were evaluated in all of the patients and FEV(1) was tested in 26 of the 37 patients. RESULTS: One to 6 operations (2.4 +/- 1.1, approximately x +/- s) were required to achieve satisfactory dilatation. After high-pressure balloon dilatation, the average airway diameter increased from (2.6 +/- 1.2) mm to (6.9 +/- 1.8) mm (P < 0.01). Dyspnea index decreased from 2.0 +/- 0.8 to 0.7 +/- 0.6 (P < 0.01). FEV(1) was increased from (1.3 +/- 0.6) L to (1.8 +/- 1.0) L (P < 0.01). No severe complications were found in these patients CONCLUSION: Bronchoplasty by high-pressure balloon dilatation through flexible fiberoptic bronchoscopy is a simple but effective and safe method to treat proximal benign tracheobronchial stenosis.

Adolescent↗
PubMed2002

[The anticancer effect of artesunate and its mechanism].

AIM: To study the anticancer effect of artesunate and its mechanism. METHODS: To observe the effect of artesunate on the growth of solid tumor and the expression of PCNA, Bcl-2 and Bax genes in mice bearing H22 solid hepatic carcinoma. RESULTS: After administration of artesunate (ig, 300 mg.kg-1.d-1 x 7 d), growth of solid tumor was obviously inhibited, the tumor inhibitory rates were 49.1%, 48.7% and 46.6% and 46.6% in 3 experiments. The apoptosis of liver cancer cells were increased. Immunohistochemical staining showed that the number of Bcl-2 protein positive cells were decreased, but the number of Bax protein positive cells were increased. The PCNA positive cells were significantly lower than those in the control group. CONCLUSION: Artesunate showed obvious anticancer activity on H22 hepatic carcinoma bearing mice and undergo apoptosis of liver cancer cells. The mechanism of anticancer effect of artesunate may be related to down-regulation of the expression of PCNA and Bcl-2 genes and up-regulation of the expression of Bax gene.

Animals↗
PubMed2002

[Long terminal repeats of retroposons in Candida albicans].

25 Candida albicans strains have been analysed on Southern hybridization patterns with alpha, beta, gamma, kappa probes. The alpha, beta, gamma, kappa, elements can be used to distinguish the differences and relations between C. albicans strains. Chromosomal localization analysis indicated that the alpha, beta, gamma, kappa, elements were located on several different chromosomes in Candida albicans strains. Northern hybridization showed that alpha, beta, gamma were transcribed actively and regulated by different stimuli. The kappa was inactive. Our results indicated that in Candida albicans there were many kinds of retroposons whose numbers and distribution were different. These retroposons could be used to identify Candida albicans strains as moleculer markers.

Blotting, Northern↗