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Biomedical subjects

W D Wang

Publications and source records attributed to W D Wang.

14 recordsLinked to original sources
PubMed2001

Ectopic expression of negative ARNT2 factor disrupts fish development.

ARNT factors are a cluster of bHLH-PAS factors that heterodimerize with other specific bHLH-PAS factors to mediate a wide range of biological responses. Previously, we obtained a truncated form of ARNT2-like factor, ARNT2A, from zebrafish, which encompasses the basic-helix-loop-helix and PAS A/B domains, but lacks a transactivation domain at its carboxyl end. Herein, we report another truncated ARNT2-like factor, ARNT2X, in zebrafish, which differs from ARNT2A at its N-terminal region. In cultured ZLE cells, transiently expressed ARNT2X and ARNT2A inhibited 2,3,7,8-TCDD-activated cyp1a1 transcription with different efficiencies. In the developing embryo, arnt2X mRNA was consistently expressed in the retinal and neural tube regions until the hatching stages, but it exhibited a more specific pattern at larval stages, including expression in the brain, eyes, hypothalamus, pharyngeal skeleton, heart, liver, pronephros duct, pectoral fin, and epithelial cells of the swim bladder. In contrast, arnt2A transcription diminished after hatching. Microinjecting a recombinant arnt2X-expression vector into fertilized eggs before cleavage stages caused severe defects in brain, eyes, pectoral fin, heart, and gut development. This suggests that the ARNT-mediated signal transduction pathways play important roles in fish tissue development.

Amino Acid Sequence↗
PubMed2001

Kinetics and mechanism of phosphine autoxidation catalyzed by imidorhenium(V) complexes.

The relative binding abilities of PY(3) (PMe(3), PMe(2)Ph, PMePh(2), PPh(3), P(OMe)(3), P(OMe)(2)Ph, PEt(3), P(OEt)(3), P(OEt)Ph(2), and dmpe) toward Re(V) were evaluated. The equilibrium constants for the reactions, MeRe(NAr)(2)[P(OMe)(3)](2) + PY(3) = MeRe(NAr)(2)(PY(3))(2) (1) + P(OMe)(3), decrease in the order PMe(3) > dmpe > PMe(2)Ph > P(OMe)(2)Ph approximately PEt(3) > P(OEt)(3) > PMePh(2) > P(OEt)Ph(2) > PPh(3). Both electronic and steric factors contribute to this trend. The equilibrium constant increases as the basicity of PY(3) increases when the steric demand is the same. However, steric effects play a major role in the coordination, and this is the reason that the affinity of PEt(3) toward Re(V) is less than that of PMe(2)Ph. A mixed-ligand complex, MeRe(NAr)(2)[P(OMe)(3)](PY(3)), was also observed in the course of the stepwise formation of 1. The large coupling constant, (2)J(PP) > or = 491 Hz, between the two phosphorus atoms suggests a trans geometry for the phosphines. Compound 1 catalyzes the oxidation of PY(3) by molecular oxygen. Kinetic studies suggest that the reaction of 1 with O(2) is first-order with respect to [O(2)] and inverse-first-order with respect to [PY(3)]. A mechanism involving a peroxorhenium intermediate MeRe(NAr)(2)(eta(2)-O(2)) is proposed for the catalytic processes. The reactivity of MeRe(NAr)(2)(eta(2)-O(2)) toward triaryl phosphines parallels that of the known compound MeReO(2)(eta(2)-O(2)).

Journal Article↗
PubMed2000

Hydrolysis, hydrosulfidolysis, and aminolysis of imido(methyl)rhenium complexes.

The tris(imido)methylrhenium complex CH3Re(NAd)3 (1a, Ad = 1-adamantyl) reacts with H2O to give CH3Re(NAd)2O (2a) and AdNH2. The resulting di(imido)oxo species can further react with another molecule of H2O to generate CH3Re(NAd)O2 (3a). The kinetics of these reactions have been studied by means of 1H NMR and UV-vis spectroscopies. The second-order rate constant for the reaction of 1a with H2O at 298 K in C6H6 is 3.3 L mol-1 s-1, which is much larger than the value 1 x 10(-4) L mol-1 s-1 obtained for the reaction between CH3Re(NAr)3 (1b, Ar = 2,6-diisopropylphenyl) and H2O in CH3CN at 313 K. Both 1a and 1b react with H2S to produce the rhenium(VII) sulfide, (CH3Re(NR)2)2(mu-S)2 (4a, R = Ad; 4b, R = Ar), with second-order rate constants of 17 and 1.6 x 10(-4) L mol-1 s-1 in C6H6 and CH3CN, respectively. Complex 4b has been structurally characterized. The crystal data are as follows: space group C2/c, a = 30.4831 (19) A, b = 10.9766 (7) A, c = 18.1645 (11) A, beta = 108.268(1) degrees, V = 5771.5 (6) A3, Z = 4. The reaction between CH3Re(NAr)2O (2b) and H2S also yields the dinuclear compound 4b. Unlike 1b, 1a reacts with aniline derivatives to give mixed imido rhenium complexes.

Journal Article↗
PubMed1998

Nitric oxide synthesis in myocardium following burn injury in rats.

We investigated nitric oxide and cyclic GMP production in myocardium early after burn injury in rats. Nitric oxide synthase activity was measured in cytosol from the left ventricular wall of burned rats. Cytosol from control group animals was shown to contain mainly Ca2+-dependent nitric oxide synthase (cNOS) with a small amount of Ca2+-independent nitric oxide synthase (iNOS). Following burn injury, there was a marked increase in iNOS activity with a peak at 8 h post-burn, however, myocardial cNOS activity was found to decline. Parallel to iNOS induction there was a significant increase in myocardial nitric oxide and cyclic GMP production. All these changes were alleviated by treatment of the rats with dexamethasone. Since increases in cyclic GMP levels in the heart were associated with reduced myocardial contractility, it is possible that enhanced production of nitric oxide by a Ca2+-independent NO synthase accounts, at least in part, for the depression of myocardial contractility seen in burn animals and patients.

Animals↗
PubMed1995

Computed tomography of pulmonary metastases from oral and maxillofacial tumors.

Computed tomographic scans were done on 14 oral and maxillofacial malignant tumors in which pulmonary metastases occurred but were poorly delineated by conventional chest radiography and tomography. Computed tomography promotes the accurate diagnosis of small and occult pulmonary metastases. Optimal nonlinear computed tomographic windows are recommended for the diagnosis of pulmonary metastases.

Adult↗
PubMed1994

Feasibility and effectiveness of a stages-of-change model in cigarette smoking cessation counseling.

Counseling coupled with a stages-of-change model in cigarette smoking cessation is a useful method for physicians to help patients stop smoking. The participants were 27 physicians, randomly assigned to three groups of nine physicians each. The first group of physicians were given two lectures on the stages-of-change model on which to base their patient counseling. The second group of physicians were not exposed to the model but a reminder reading "Ask your patients to stop smoking" was placed in their clinic. The third group of physicians were neither exposed to the model nor given any reminder. Of the 93 smokers among the patients of the 27 physicians, 39 were in the first group, 26 in the second, and 28 in the third. A survey indicated that among the three groups there was no significant difference in demographic data, cigarette smoking history, and personal attitude toward smoking cessation counseling. At the end of six months, the first group of patients accomplished a quit smoking rate of 28.6%; of the patients still smoking 56% had decreased their daily cigarette consumption. The corresponding figures for the second group were 8.3% and 9.1%. The corresponding figures for the third group were 4.3% and 13.6%. These data show that counseling coupled with the concept of a stages-of-change model is feasible and effective to assist with cigarette smoking cessation.

Adult↗
PubMed1994

[Differential diagnosis between infection and neoplasm of the infratemporal fossa].

Because there are many similarities in infection and neoplasm of the infratemporal fossa (ITF), it is difficult to differentiate between these two diseases. By analysing 28 cases of the ITF lesions (8 cases of infection, 20 cases of neoplasm) the authors find the following points are important to differentiate between infection and neoplasm of the ITF. 1. The patients suffering from ITF infection almost all have odynophagia, while the patients suffering from the ITF neoplasm have no such symptom. The latter presents numbness in branches of the fifth nerve, while the former scarcely exhibits this symptom. 2. In the ITF neoplasm the mass could be found by CT or MRI, while in the ITF cellulitis no mass could be found. Although CT or MRI could find the mass in the ITF abscess, at the same time CT definitely could find some imaging signs which signify infection such as abscess formation (lucency) and gas bubbles. CT could find adjacent bone destruction in most ITF neoplasms, while this is rare in (ITF) infection. MRI is very helpful in differentiating between these two.

Carcinoma, Squamous Cell↗
PubMed1991

Differential ability of proximal and remote element pairs to cooperate in activating RNA polymerase II transcription.

To investigate the synergism or cooperative interaction between transcription elements, we have designed and constructed a series of synthetic polymerase II promoters with different combinations of elements. These include three different CCAAT boxes, which correspond to the binding sites for CP1, CP2, and NFI, a GC box, a CACCC box, and an ATF/CREB-binding site. The synthetic promoters containing these elements in proximal positions were linked to a test gene (CAT). Tandem repeats of AP1- and AP2-binding sites, the simian virus 40 enhancer, and DNA-binding sites for GAL-estrogen receptor were cloned downstream of the test gene. The strength of these promoters was then tested in transient-expression assays in HeLa TK- cells. In the context of the adenovirus major late promoter TATA box, the promoters containing only certain combinations of elements are active in this assay. Some elements appear to cooperate nearly universally, but others exhibit strong selectivity. These results indicate strongly selective synergistic interactions between elements and suggest that levels of promoter strength may be determined by the extent of compatibility between factors bound to proximal and enhancer sites.

Base Sequence↗
PubMed1991

[Rapid percutaneous trough-needle biopsy of lesions in the lung--report on 68 cases].

The results of rapid percutaneous trough-needle biopsy of lung lesions in 68 cases (76 punctures) is reported. It was successful in 60 of the 68 cases (89.1%). After localizing the lesion on the simulator, TV screen of X-ray machine, or chest film, the procedure was performed with the X-ray switched off. Pneumothorax was observed in 8 cases (8/76 punctures, 10.5%) by routine chest film taken 1 1/2-2 hours after biopsy. 4 patients were asymptomatic (atelectasis below 20%). Pneumothorax could be induced if the needle was at an acute angle with the surface of the pleura at the time of puncture. The needle should pierce the pleura perpendicularly. Premature removal of the pith with the slot tip half-through the pleura might have been another cause of pneumothorax. As the movement of a coin lesion is wide during respiration, the patient must be trained to hold his breath at the end of inspiration or expiration and remains so during the puncture. The chance of success in puncturing a coin lesion could be increased if the lesion is so immobilized and visualized as it is pin-pointed with the rib out of the way at the time of puncture.

Adolescent↗
PubMed1989

A study on the standard for forensic anthropologic identification of skull-image superimposition.

By means of X-ray photography tests were made of 224 (100 males and 124 females) volunteer Chinese adults of Han nationality to study the related regular patterns of superimposed projection of face landmarks onto the skull. On the basis of these tests, the present article reveals from a forensic anthropology angle the related regular patterns of plane projection of the human face with its skull. Study shows that there exist a strict individual identity and exclusiveness in relation between the human face and skull. The related regularity of displacement of face landmarks appears in projection of the skull with the human head at different photographic positions and angles. On the basis of this discovery, 52 indexes in 4 groups were established as a standard for judging the identification of a skull's body origin by means of skull-image superimposition. Based on forensic anthropology, the technique has raised to a great extent the credibility of unknown skull identification. In the past 8 years, 89 unknown skulls have been identified with their body origins which provided important and accurate evidence for the solution of murders with dismembered bodies, skeletonized bodies, and unidentified dead bodies.

Adult↗
PubMed1986

Endogenous microbial dissemination following severe burns in rats.

This study suggests that damage to the intestinal lining, an important mechanical barrier against bacterial invasion, is the main factor leading to the dissemination of endogenous microbes. Reduced phagocytic activity of Kupffer cells and compromised opsonic function also appear to contribute to the process.

Animals↗
PubMedDate not supplied

Membrane proteins at the interface of erythrocytes fused by treatment with polyethylene glycol.

Fusion of human red cells through the action of polyethylene glycol gives rise to pairs or higher clusters with a common membrane envelope, in which a barrier at the position of the original interface can be seen in phase contrast. At early times this septum contains lipids, as judged by labelling with a fluorescent lipophile, and transmembrane protein; this was shown by the presence of the preponderant component, band 3, detected by a fluorescent label, covalently attached before fusion at an extracellular site, or by immunofluorescence with anti-band 3 antibody. Ankyrin, which is bound to band 3, is also observed in the septum. The lipid thereafter disappears from the interface, carrying most of the band 3 with it. A continuous membrane skeletal network, defined by the presence of spectrin (detected by immunofluorescent staining in epifluorescence and confocal microscopy) appears to persist for long periods, but in many cells interruptions develop in the septum. In other fused pairs, particularly at longer times, the interface is seen to have vanished completely. Protease inhibitors have no discernible effect on any of these observations. The results suggest a model for the events that follow fusion. Covalent cross-linking of membrane proteins beyond a critical level causes inhibition of fusion, suggesting that proteins, probably the membrane skeletal network, regulate the fusion process. The efficiency of fusion is strikingly dependent on the composition of the isotonic medium, being relatively high at an orthophosphate concentration of 5 mM and minimal at 20 mM.

Anion Exchange Protein 1, Erythrocyte↗