PubMed Health⌕ Search

Biomedical subjects

D M Wang

Publications and source records attributed to D M Wang.

At least 19 recordsLinked to original sources
PubMed2006

Community-acquired pneumonia in Shanghai, China: microbial etiology and implications for empirical therapy in a prospective study of 389 patients.

The aim of this multicenter study was to identify the causative pathogens of community-acquired pneumonia (CAP) in Shanghai, China, and to determine their susceptibility to antimicrobial agents. Pathogens obtained from 389 patients with documented CAP during 2001-2003 were identified by multiple diagnostic tools that included bacterial culture, polymerase chain reaction (PCR), and specific immunological assays. Susceptibility of the bacterial isolates was tested by the broth microdilution method. A specific pathogen was identified in 39.8% (155/389) of the patients: Haemophilus influenzae (n=80), Klebsiella spp. (n=15), Streptococcus pneumoniae (n=12), Staphylococcus aureus (n=6), Moraxella catarrhalis (n=1), other gram-negative organisms (n=9), and atypical pathogens that comprised Mycoplasma pneumoniae (n=42), Chlamydia pneumoniae (n=17), and Legionella pneumophila (n=2). Most H. influenzae isolates were susceptible to ampicillin (88.3%), and all were susceptible to macrolides. Of the S. pneumoniae isolates, 75% (9/12) were susceptible to penicillin, while 25% (3/12) were intermediately susceptible. H. influenzae and atypical pathogens are among the most important pathogens of CAP. Ampicillin, cephalosporins, and the newer fluoroquinolones can be used as empirical therapy for CAP in the Shanghai area. The efficacy of monotherapy with newer macrolides for CAP caused by S. pneumoniae requires further evaluation.

Adolescent↗
PubMed2005

A 'Chinese Spring' wheat (Triticum aestivum L.) bacterial artificial chromosome library and its use in the isolation of SSR markers for targeted genome regions.

A bacterial artificial chromosome (BAC) library was constructed from the bread wheat (Triticum aestivum L.) genotype 'Chinese Spring' ('CS'). The library consists of 395,136 clones with an estimated average insert size of 157 kb. This library provides an estimated 3.4-fold genome coverage for this hexaploid species. The genome coverage was confirmed by RFLP analysis of single-copy RFLP clones. The CS BAC library was used to develop simple sequence repeat (SSR) markers for targeted genome regions using five sequence-tagged-site (STS) markers designed from the chromosome arm of 3BS. The SSR markers for the targeted genome region were successfully obtained. However, similar numbers of new SSR markers were also generated for the other two homologous group 3 chromosomes. This data suggests that BAC clones belonging to all three chromosomes of homologous group 3 were isolated using the five STS primers. The potential impacts of these results on marker isolation in wheat and on library screening in general are discussed.

Chromosomes, Artificial, Bacterial↗
PubMed2005

Study on changes of heme oxygenase-1 expression in patients with coronary heart disease.

BACKGROUND: Heme oxygenase (HO) is a rate-limiting enzyme of endogenetic carbon monoxide (CO) that degrades heme into carbon monoxide, bilirubin, and iron. These products have important physiologic effects: bilirubin is a potent antioxidant that can act against ischemia/reperfusion injury; there is a negative correlation between the content of HO-1 and the incidence of coronary heart disease (CHD). HYPOTHESIS: This study was undertaken to investigate the changes of HO-1 in patients with CHD. METHODS: Thirty-five patients with acute myocardial infarction (AMI), 40 patients with unstable angina pectoris (UAP, diagnosed by coronary angiography), and 30 patients with stable angina pectoris (AP, diagnosed by coronary angiography) were selected for the study; another 30 patients with normal coronary artery (diagnosed by coronary angiography) were selected as controls. The levels of HO-1 protein expression in monocyte and lymphocyte in the subjects were tested by immunohistochemistry and western blot. Computer picture analyzing systems were also used to measure the levels of HO-1 protein expression. RESULTS: Heme oxygenase-1 protein is located in cell plasma. The levels of HO-1 protein expression in patients with CHD were significantly higher than in those without CHD (p < 0.01). There were significant differences of HO-1 expression among the three groups of patients with CHD. The group with AMI was the highest, followed by the group with UAP and finally by the group with AP. CONCLUSIONS: There is a higher expression of HO-1 in patients with CHD. The levels of HO-1 protein are associated with the severity of CHD.

Biomarkers↗
PubMed2005

Molecular genetic analysis for Ax phenotype of the ABO blood group system in Chinese.

BACKGROUND AND OBJECTIVES: To elucidate the molecular genetic background of the Ax phenotype in the Chinese population. MATERIALS AND METHODS: The ABO genes of eight Ax phenotype samples, four Ax and four AxB, were amplified by polymerase chain reaction (PCR) and were cloned, along with those of 10 random A(1) Chinese subjects. We analysed the ABO gene transcript structure and the sequences of two exons and one intron at the ABO locus. RESULTS: Among the four Ax phenotype samples, we identified one Ax02, two Ax03 and one novel Ax allele with the 543G > T mutation in the A102 background. Two of five family members also carry the allele. Of the four AxB phenotypes, one was designated as cis-AB-1/B101; the other three were shown to carry one B allele and one O with the nt261G deletion. The B alleles of the latter three were identical to B101 except for single point mutation at nt700C > G, nt640A > G and nt641T > C, respectively. The novel B101-like alleles were first associated with A(weak)B phenotypes. CONCLUSIONS: Two ABO*B(A) alleles and an Ax allele clearly differ from all previously reported ABO alleles, suggesting that the molecular genetic background of Ax is heterogeneous in the Chinese population.

ABO Blood-Group System↗
PubMed2004

The influence of plasticizers on the release of theophylline from microporous-controlled tablets.

The aim of present work was to investigate the influence of plasticizer on the release of theophylline from microporous-controlled tablets. Three plasticizers, acetyltributyl citrate (ATBC), castor oil, and triacetin, were included in this study. These plasticizers reduced the crystallinity of poly(epsilon-caprolactone) (PCL)/poly(ethylene glycol) (PEG)-blended films, and the most prominent change of enthalpy of fusion was the film plasticized by triacetin. This might be due to triacetin penetrating into both PCL and PEG domains. However, the lipophilic property of castor oil only allowed it to alter the crystallization of hydrophobic PCL domain. The Young's modulus and the tensile strength of films showed a decreased tendency while increasing the amount of plasticizer. The change of elongation of plasticized blended films was irregular and was dependent of the type of plasticizer. The size of micropores formed in the presence of plasticizer was larger than those micropores formed in its absence. The fatty plasticizer, castor oil, altered the thermal and mechanical performance and pore size of films via soluble in PCL domain, which resulted in the release of theophylline from castor oil plasticized-coated tablets, which in turn enhanced and closed to a constant release pattern.

Caproates↗
PubMed1999

Transformation by v-Myb.

The v-myb oncogene of the avian myeloblastosis virus (AMV) is unique among known oncogenes in that it causes only acute leukemia in animals and transforms only hematopoietic cells in culture. AMV was discovered in the 1930s as a virus that caused a disease in chickens that is similar to acute myelogenous leukemia in humans (Hall et al., 1941). This avian retrovirus played an important role in the history of cancer research for two reasons. First, AMV was used to demonstrate that all oncogenic viruses did not contain a single cancer-causing principle. In particular, although both Rous sarcoma virus (RSV) and AMV could replicate in cultures of either embryonic fibroblasts or hematopoietic cells, RSV could transform only fibroblasts whereas AMV could transform only hematopoietic cells (Baluda, 1963; Durban and Boettiger, 1981a). Second, chickens infected with AMV develop remarkably high white counts and therefore their peripheral blood contains remarkably large quantities of viral particles (Beard, 1963). For this reason AMV was often used as a prototypic retrovirus in order to study viral assembly and later to produce large amounts of reverse transcriptase for both research and commercial purposes. Following the discovery of the v-src oncogene of RSV and the demonstration that it arose from the normal c-src proto-oncogene, a number of acute leukemia viruses were analysed by similar techniques and found to also contain viral oncogenes of cellular origin (Roussel et al., 1979). In the case of AMV, it was shown that almost the entire retroviral env gene had been replaced by a sequence of cellular origin (initially called mab or amv, but later renamed v-myb) (Duesberg et al., 1980; Souza et al., 1980). Remarkably, sequences contained in this myb oncogene were shared between AMV and the avian E26 leukemia virus, but were not contained in any other acutely transforming retroviruses. In addition, the E26 virus contained a second sequence of cellular origin (ets) that was unique. The E26 leukemia virus was first described in the 1960s and causes an acute erythroblastosis in chickens, more reminiscent of the disease caused by avian erythroblastosis virus (AEV) than by AMV (Ivanov et al., 1962).

Animals↗
PubMed1999

Functional analysis of carboxy-terminal deletion mutants of c-Myb.

The c-myb gene is implicated in the differentiation and proliferation of hematopoietic cells. Truncations of the N and/or C terminus of c-Myb, found in v-Myb, can potentiate its transforming ability. Two negative regulatory subregions, located in the C terminus, were mapped previously by using GAL4-c-Myb fusion proteins in transient transfection assays for the transcriptional activation of a GAL4-responsive reporter gene. To dissect the C terminus of c-Myb in terms of its involvement in transcriptional activation and oncogenic transformation, a series of C-terminal deletion mutants of c-Myb were analyzed. In addition, linker insertion mutants within the transactivation domain and/or heptad leucine repeat of c-Myb were examined along with those deletion mutants. In this study, we demonstrated that the removal of both of the two previously mapped negative regulatory subregions from the native form of c-Myb not only supertransactivates a Myb-responsive reporter gene but also potentiates its transforming ability in culture. However, in contrast to previous results, cells transformed by all of the mutants analyzed here except v-Myb itself exhibited the same phenotype as those transformed by c-Myb. The proliferating cells were bipotenial and differentiated into both the granulocytic and monocytic lineages. This result implies that the C terminus of c-Myb alone has no effect on the lineage determination. Finally, the transactivation activities of these mutants correlated with their transforming activities when a mim-1 reporter gene was used but not when a model promoter containing five tandem Myb-binding sites was used. In particular, a very weakly transforming mutant with a linker insertion in the heptad leucine repeat superactivated the model promoter but not the mim-1 reporter gene.

Animals↗
PubMed1998

Application of asymmetric TPX membranes to transdermal delivery of nitroglycerin.

In this study, asymmetric poly(4-methyl-1-pentene) (TPX) membranes, fabricated by the dry/wet inversion method, were applied to transdermal delivery of nitroglycerin (NTG), a drug for treating angina pectoris. The flux of NTG through the TPX membrane was measured in vitro by a Franz cell. The results indicate that the NTG flux through asymmetric TPX membranes is strongly dependent on the membrane structure, which can be varied by adding nonsolvents in the casting solution. By adding different kinds of nonsolvents and adjusting the added amounts, membranes with different NTG release rates can be fabricated. It was also found that, with suitable drug formula, the NTG dissolution rate of a prototype TPX patch is comparable to that of a commercial patch, Transderm-Nitro. In addition, the data of NTG flux through a composite of TPX membrane and pig skin are also presented.

Animals↗
PubMed1997

Cells transformed by a v-Myb-estrogen receptor fusion differentiate into multinucleated giant cells.

In order to make conditional alleles of the v-myb oncogene, we constructed and tested avian retroviruses which produce a number of different fusion proteins between v-Myb and the human estrogen receptor (ER). We found that the portion of the ER used in making these fusions profoundly affected their transcriptional activation. However, all the fusions tested were only weakly transforming in embryonic yolk sac assays and there was no direct correlation between the level of transcriptional activation and strength of oncogenic transformation. Nevertheless, transformation by a v-Myb-ER fusion was estrogen dependent, and upon withdrawal of the hormone, monocytic-lineage cells differentiated into multinucleated giant cells. Surprisingly, the withdrawal of estrogen caused a dramatic increase in the stability of the fusion protein, although it remained unable to promote cell growth or block differentiation.

Animals↗
PubMed1996

Members of the caudal family of homeodomain proteins repress transcription from the human apolipoprotein B promoter in intestinal cells.

Apolipoprotein B (apoB) is the major protein component of low density lipoproteins, and plays a central role in cholesterol transport and metabolism. The apoB gene is transcribed in the liver and in the intestine in humans. Although much is known about the DNA sequence elements and protein factors that are important for transcription of the human apolipoprotein B gene in the liver, less is known about the mechanisms that control transcription of this gene in the intestine. The sucrose isomaltase gene (SI), is expressed exclusively in the intestine. Two sequences from the promoter region of the SI gene, namely SIF-1 and SIF-3, are essential for promoter activity of the SI gene in intestinal cells. Sequences displaying a high degree of similarity to those of SIF-1 and SIF-3 are present in the third intron of the apoB gene. Rather than stimulating apoB promoter activity, the BSIF-1 and BSIF-3 sequences repressed transcription in CaCo-2 cells. Gel retardation studies demonstrated that BSIF-1, like SIF-1, binds to proteins related to the caudal family of proteins such as mCdx-4 and mCdx-2. These proteins appear to repress transcription from the apoB promoter by a mechanism that involves an interaction with members of the C/EBP family of proteins, that bind to a target sequence for the repressor in the segment from -139 to -111 of the apoB promoter. On the other hand, BSIF-3, like SIF-3, binds to HNF-1 and also represses transcription from the apoB promoter.

Apolipoproteins B↗
PubMed1996

Evaluation of the function of the human apolipoprotein B gene nuclear matrix association regions in transgenic mice.

The human apolipoprotein B (apoB) gene resides in a 47.5 kb DNasel-sensitive chromosomal domain in hepatic and intestinal cells, flanked by the 5' distal matrix association region (MAR) and the 3' proximal MAR. A third MAR, the 5' proximal MAR, is found only in transcriptionally active hepatic (HepG2) cells. Hepatic expression of the apoB gene requires a tissue-specific promoter (-898 to +121) and an enhancer from the second intron of the gene (+360 to +1064). A vector containing this portion of the gene linked to the beta-galactosidase reporter is sufficient for low level expression in the livers of transgenic mice. Expression in transgenic mice was increased when the promoter-enhancer beta-gal vector was flanked by MARs. The results were similar whether the 5' distal, the 5' proximal or the 3' proximal MARs were placed at both ends of the construct, or whether the construct was flanked by the 5' distal and the 3' MAR, suggesting that the apoB MARs play a role in gene expression in vivo. When the MAR-containing constructs were transiently transfected into HepG2 cells, the resulting beta-gal activities were similar to that of the construct lacking MARs, thus demonstrating that the MARs do not exhibit any enhancer activity. Recent experiments (Kalos, M., and R. E. K. Fournier. 1995. Mol. Cell. Biol. 15: 198-207) examining stable integration of some of our constructs into human and rat hepatoma transfectants suggest that in single and double copy transfectants, the apoB MARs behave as boundary "insulators", protecting the integrated transgenes against position effects regardless of their site of integration. However, multicopy transfectants are transcriptionally inactive and when the MARs are absent, expression of the transgenes drops to background levels. Our results to date with single and low-copy number transgenes do not support an insulator function for the apoB MARs, although they appear to be required to increase the levels of expression.

Animals↗
PubMed1995

Nonlinear analysis of oscillatory flow, with a nonzero mean, in an elastic tube (artery).

Oscillatory flow of a Newtonian fluid in an elastic tube, which is a model of blood flow in arteries, is analyzed in this paper. For a rigid tube, the steady flow field can be described by Poiseuille's law and the unsteady flow field by Womersley's solution. These are the linearized solutions for flow in elastic tubes. To evaluate the importance of nonlinear effects, a perturbation solution is developed realizing that the amplitude of arterial wall movement is small (typically 5-10 percent of the diameter). The nonlinear effects on the amplitude of the wall shear rate, on the amplitude of the pressure gradient, and on the mean velocity profile have been considered. Nonlinear effects on the oscillatory components depend on Womersley's unsteadiness parameter (alpha), the ratio between the mean and amplitude of the flow rate, the diameter variation, and the phase difference between the diameter variation and the flow rate (phi) which is indicative of the degree of wave reflection. On the other hand, the mean velocity profile is found to be dependent on the steady-streaming Reynolds number, Rs. When Rs is small, the mean velocity profile is parabolic (1-xi 2); however, when Rs is large, the velocity profile is distorted by the nonlinear effect and can be described by sin (pi xi 2). The increase of the amplitude and reduction of the mean of wall shear rate as phi changes from 0 to -90 deg suggests an indirect mechanism for the role of hypertension in arterial disease: hypertension-->increased wave reflection-->wall shear stress is reduced and more oscillatory.

Arteries↗
PubMed1995

Modeling interstitial flow in an artery wall allows estimation of wall shear stress on smooth muscle cells.

The arterial media is modeled as a periodic array of cylindrical smooth muscle cells residing in a matrix comprised of proteoglycan and collagen fibers. Using Brinkman's model to describe transmural flow through such a fibrous media, we calculate the effective hydraulic permeability of the media and the wall shear stress on smooth muscle cells. Two interesting results are obtained: first, the wall shear stress on smooth muscle cells is on the order of 1 dyne/cm2, which is the range known to affect endothelial cells in vitro; second, the flow resistance due to smooth muscle cells is not negligible compared to the resistance due to the fiber matrix.

Arteries↗
PubMed1995

[HPLC determination of 4-[4"-(2",2",6",6"-tetramethyl-1"-piperidinyloxy) amino]-4'-demethylepipodophyllotoxin in rat plasma and studies of its pharmacokinetics].

4-[4"-(2",2",6",6"-tetramethyl-1"-piperidinyloxy) amino]-4'- demethylepipodophyllotoxin (GP-7) is a new podophyllotoxin spin-labeled derivative. Its primary effect is the antitumor activity on transplanted mouse tumors and cultured tumor cells. This paper describes a method for its determination using HPLC with UV detection and the determination of its pharmacokinetic parameters in rats. A Shimadzu LC-6A liquid chromatograph equipped with a Shimadzu SPD-6AV multiwavelength detector and a Chromatopac C-R3A data processor was used. The separation was performed on a Zorbax-ODS column (5 microns, 4.6 mm x 150 mm) with a mobile phase of methanol--water--glacial acetic acid (59:41:0.6). The flow-rate was 1.0 ml.min-1 and detection was made at 285 nm. A plasma specimen (0.2 ml) was spiked with 22.6 micrograms.ml-1 internal standard (podophyllic acid piperidinyl hydrazone nitroxide radical, GP-1) and extracted with ether--dichloromethane (3:1). The extract was evaporated at 45 degrees C. The residue was taken up with 0.1 ml of the mobile phase and 20 microliters aliquots were injected into the system. The calibration curve was linear in the range from 2 to 200 micrograms.ml-1 with r = 0.9997. The detection limit was 0.2 microgram.ml-1 and the recovery of GP-7 from rat plasma was 94.3%-100.9%. The relative standard deviations for within- day and between-day were 2.29%-4.64% and 5.55%-7.70%, respectively. After iv injection of GP-7 10, 20 and 30 mg.kg-1, the concentrations of the drug in rat plasma were determined. The pharmacokinetic parameters of GP-7 were obtained by using MCPKP program on a COMPAC-486 computer. The data obtained fitted a two-compartment open model, and the mean T1/2 beta value was 39.8 +/- 10.8 min.

Animals↗
PubMed1994

Hemodynamics and wall shear rate in the abdominal aorta of dogs. Effects of vasoactive agents.

Vasoactive drugs are known to affect impedance (pressure/flow) and vessel wall motion in arteries. The nonlinear theory of oscillatory flow in straight elastic vessels indicates that wall shear rate is affected by changes in impedance phase angle and wall motion. To test whether wall shear rate depends on impedance phase angle and wall motion in vivo, wall shear rate was measured in the abdominal aorta of anesthetized dogs by using a flush-mounted hot-film anemometer, and the hemodynamic state was characterized by pressure, flow, and vessel dimension measurements. Vasodilators (nitroprusside and isoproterenol) and vasoconstrictors (angiotensin II and norepinephrine) were administered acutely, and the responses of wall shear rate and hemodynamics were determined. In the control state (no drugs), peak wall shear rate was 1835 +/- 153 s-1 (mean +/- SEM). The vasodilators induced large increases in impedance phase angle and wall motion concomitant with large increases in peak wall shear rate (62.4 +/- 20.4% for nitroprusside and 68.9 +/- 28.3% for isoproterenol), which were not predicted accurately by Womersley's theory of oscillatory flow in a rigid vessel or the nonlinear theory of oscillatory flow in an elastic vessel, with measured flow and vessel dimension used as inputs. The vasoconstrictors induced small decreases in impedance phase angle and wall motion and small changes in peak wall shear rate (increase, 30.5 +/- 8.0% for norepinephrine; decrease, 18.2 +/- 7.1% for angiotensin II), which were predicted accurately by Womersley's theory. The present study shows that vasoactive drugs, particularly vasodilators, can have significant effects on wall shear rate (stress) in the abdominal aorta that appear to be related to changes in impedance phase angle and vessel wall motion. However, the effects on wall shear rate are not predicted accurately by straight-tube theory.

Angiotensin II↗
PubMed1994

Cardiac function and histological changes after non-dynamic cardiomyoplasty and preliminary study of dynamic cardiomyoplasty.

By means of histological method and ultrasound cardiographic (UCG) examination, the left-right ratio of transectional area of muscle fiber of latissimus dorsi muscle (LDM) after non-dynamic cardiomyoplasty was 77.4 +/- 11.7% in Group I (3 weeks after operation), and 78.4 +/- 11.6% atrophy and hyperplasia of LDM, but the basical structure was retained. The ejection fraction (EF) decreased significantly after operation (P < 0.05), but the difference between two groups was non- significant. Also, dynamic cardiomyoplasty was performed on a sheep. UCG showed the increased cardiac systolic function after operation. ATPase, succinodehydrogenase (SDH) and PAS examination implied the strengthening of fatigue-resistant ability in skeletal muscles after long-term electrical stimulation. So cardiomyoplasty is suggested to be a supplementary measure in treating end-stage heart failure.

Animals↗
PubMed1994

The adenovirus E1A 289R and 243R proteins inhibit the phosphorylation of p300.

A protein of 300 kDa (p300) associates with the adenovirus E1A proteins and has been implicated in the control of cell cycle progression. In mammalian cells, p300 is actively phosphorylated in both quiescent and proliferating cells and its level of phosphorylation increases as it travels from late G1 into M phase. E1A requires p300 for the induction of cellular DNA synthesis and the repression of enhancer mediated transcription, suggesting that p300 may be involved in pathways that are important to cell proliferation and gene expression. Since the activities of most cell cycle regulatory proteins depend on their phosphorylation state, the possibility exists that certain activities of p300 might also be controlled by phosphorylation and that E1A might in fact be affecting these events. We show here by in vitro analysis that E1A inhibits the phosphorylation of p300 by decreasing the rate of incorporation of phosphate into p300. We also show that p300 can be used as a substrate for the cyclin-dependent p33cdk2 and p34cdc2 kinases, and propose that E1A might be antagonistic to these enzymes in phosphorylating p300. Thus, these results indicate a possible novel function by which E1A can interfere with cellular pathways.

Adenosine Triphosphate↗