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Biomedical subjects

D M Wang

Publications and source records attributed to D M Wang.

At least 37 records · Page 2Linked to original sources
PubMed1993

An epidemic of encephalitis and meningoencephalitis in children caused by echovirus type 30 in Shanghai.

An outbreak of viral central nervous system infection occurred from May to September, 1991 in Shanghai, China. Totally 376 cases were admitted into our hospital, 54% with encephalitis and 46% with meningoencephalitis. Echovirus type 30 was isolated from CSF and stools of the patients. Only 3 of the patients were under 1 year of age. CSF examination revealed the cell count from 0-1600 x 10(6)/L. Interestingly, 9 had CSF PMNs over 90% and 13 had low sugar levels. EKG was randomly done in 20 patients and 15 demonstrated myocarditis. The outcome was uneventful in all except 1 who had psychological problem at the time of discharge.

Adolescent↗
PubMed1992

Expression of the adenovirus E1B 175R protein and its association with membranes of Escherichia coli.

The E1B 175-amino-acid (175R) protein of adenovirus 2 is required for cellular transformation of primary cells and establishing cell morphology in lytically infected cells. To investigate the biochemical function of this protein, we constructed a bacterial expression vector (pKHB1-T) to produce the 175R protein in sufficient amounts for purification and biochemical analysis. On the basis of DNA sequencing, gel electrophoresis, and immunoblot analysis, the pKHB1-T-encoded 175R protein appears to be identical to that expressed transiently in mammalian or adenovirus-transformed cells. The bacterially produced viral protein was also found to be quite stable and without any modifications. Partial purification of the pKHB1-T-encoded protein revealed that the majority of its associates with the inner membrane of the bacterial cell. This, together with the possibility of the 175R protein containing an N-terminal amphipathic alpha-helix as a potential translocation signal, suggests that there may be a common mechanism of protein transport operating in both eucaryotic and procaryotic systems.

Adenoviridae↗
PubMed1992

The adenovirus E1A 243R protein purified from Escherichia coli under nondenaturing conditions is found in association with dnaK.

The adenovirus E1A 243R protein immortalizes primary cells in culture and induces part of the phenotypes required for transformation. It has also been shown to interact with a number of cellular polypeptides, including the product of the retinoblastoma gene. To understand more fully the molecular activities of the E1A 243R protein in association with these proteins as well as its role in the processes of cellular growth, we have developed a method for rapidly purifying this protein from genetically engineered Escherichia coli under nondenaturing conditions. The plasmid-encoded E1A protein, when expressed in a protease-deficient mutant, is found to have the same length and amino acid sequence as that which is produced in a mammalian cell. The procedure for purifying the E1A 243R protein from bacteria relies primarily upon immunoaffinity chromatography and the use of a peptide comprising the epitope recognized by an E1A-specific antibody. Elution of the E1A protein under this condition allows for gentle isolation and a purity that ranges from 90 to 96%. However, without the addition of micromolar amounts of ATP prior to its elution from the antibody column, the E1A protein is found in association with an E. coli protein of 70 kDa. Immunoblot analysis with a specific antibody showed that this bacterial protein was the heat shock protein dnaK, which is known to have extensive homology with the hsp-hsc70 family of proteins in mammalian cells. Recognition of E1A by the dnaK protein may very well reflect a situation that also occurs between the mammalian heat shock proteins and the E1A 243R protein after adenovirus infection.

Adenovirus E1A Proteins↗
PubMed1992

Numerical analysis of flow in an elastic artery model.

Oscillatory and pulsatile flows of Newtonian fluids in straight elastic tubes are simulated numerically with the aid of Ling and Atabek's "local flow" assumption for the nonlinear convective acceleration terms. For the first time, a theoretical assessment of the local flow assumption is presented, and the range of validity of the assumption is estimated by comparison with perturbation solutions of the complete flow problem. Subsequent simulations with the local flow model indicate that the flow field and associated wall shear stress are extremely sensitive to the phase angle between oscillatory pressure and flow waves (impedance phase angle). This phase angle, which is a measure of the wave reflection present in the system, is known to be altered by arterial disease (e.g., hypertension) and vasoactive drugs. Thus, the paper elucidates a mechanism by which subtle changes in systemic hemodynamics (i.e., phase angles) can markedly influence local wall shear stress values.

Aorta↗
PubMed1991

A purified adenovirus 289-amino-acid E1A protein activates RNA polymerase III transcription in vitro and alters transcription factor TFIIIC.

We have previously demonstrated that a purified bacterially synthesized E1A 289-amino-acid protein is capable of stimulating transcription from the promoters of genes transcribed by RNA polymerase II in vitro (R. Spangler, M. Bruner, B. Dalie, and M. L. Harter, Science 237:1044-1046, 1987). In this study, we show that this protein is also capable of transactivating in vitro the adenovirus virus-associated (VA1) RNA gene transcribed by RNA polymerase III. Pertinent to the transcription of this gene is the rate-limiting component, TFIIIC, which appears to be of two distinct forms in uninfected HeLa cells. The addition of an oligonucleotide containing a TFIIIC binding site to HeLa whole-cell extracts inhibits VA1 transcription by sequestering TFIIIC. However, the addition of purified E1A to extracts previously challenged with the TFIIIC oligonucleotide restores the level of VA1 transcription. When included in the same reaction, an E1A-specific monoclonal antibody reverses the restoration. Incubation of purified E1A with either HeLa cell nuclear or whole-cell extracts alters the DNA-binding properties of TFIIIC as detected by gel shift assays. This alteration does not occur if E1A-specific antibody and E1A protein are added simultaneously to the extract. In contrast, the addition of this antibody to extracts at a later time does not reverse the alteration observed in the TFIIIC binding activities. Never at any time did we note the formation of novel TFIIIC-promoter complexes after the addition of E1A to nuclear extracts. These results clearly establish that E1A mediates its effect on VA1 transcription through TFIIIC in a very rapid yet indirect manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenovirus Early Proteins↗
PubMed1991

Duration of appearance of Vi antigen and Salmonella typhi in blood and urine of infected models.

Salmonella typhi (S typhi) infected models were established to evaluate the latex agglutination test (LAT) and staphylococcal coagglutination test (SCT) for the detection of S typhi Vi antigen in blood and urine. Antigens in serum or urine were detected within 7 days after infection with positive cultures, and decreased in 2 weeks. LAT and SCT were positive in 7 mice with no bacteria isolation from blood and urine but their spleen aspirates yielded S typhi. Both tests are rapid and sensitive and may be used for the diagnosis of typhoid infection, especially in partially treated patients when their blood cultures are negative.

Agglutination Tests↗
PubMed1990

Heritability of blood pressure in 7- to 12-year-old Chinese twins, with special reference to body size effects.

Systolic and diastolic blood pressures and body-size indices such as body height, body weight, sitting height, chest circumference, skinfold thickness, and body mass index (BMI) were assessed in 110 pairs of like-sex Chinese twins (75 monozygotic and 35 dizygotic) aged 7-12 years. Significant correlations of blood pressure with body-size indices were found. Prior to adjusting for body-size effects, three twin methods yielded low heritability estimates for both systolic (0.32-0.41) and diastolic (0.32-0.51) pressures. Adjusting systolic pressure for body height and BMI via multiple regression nearly halved heritability estimates, but adjusting diastolic pressure for body height and skinfold thickness only changed the estimates slightly.

Blood Pressure↗
PubMed1990

In vitro study of the influence of radial wall motion on wall shear stress in an elastic tube model of the aorta.

The purpose of this study was to determine the influence of radial motion of an arterial wall on the shear stress that flowing blood imposes on the wall (wall shear stress). Wall shear stress is known to influence endothelial cell function and may play a role in atherogenesis, but its magnitude and distribution in the circulation are not well understood. To simulate arterial wall motion, we used both straight and curved rubber tubing models in a mock circulatory system incorporating a variable impedance element distal to the model aorta. Wall shear rate was measured with a hot-film anemometer probe mounted flush on the tubing wall and free to move with the wall. Wall shear stress was determined as the product of wall shear rate and viscosity. By changing the distal impedance element, we determined the influence of the (temporal) phase angle between pressure and flow, or equivalently, tube diameter and flow, on wall shear stress. We observed a fivefold increase in peak wall shear stress and the onset of intense wall shear stress reversal sinusoidal flows as the phase angle between pressure and flow was reduced from -60 degrees to -80 degrees. Wall shear stresses were insensitive to this same phase angle when its value was between -10 degrees and -60 degrees. Theoretical predictions, also presented here, are in accord with these observations. The phenomena we have observed in elastic tubes may be important in the arterial system because the phase angle between the first harmonic of pressure and flow in the aorta of humans is usually near our sensitive range. This same phase angle becomes more negative in hypertensive patients and is influenced by vasoactive drugs.

Aorta↗
PubMed1990

[Study on prolonged action cefotoxime].

A prolonged action cephalosporin was prepared by the reaction of cefotaxime sodium (CTX) with N,N-dibenzylethylene diamine acetate. It is reasonable to consider the resultant as benzathine cefotaxime (BCTX) by means of elemental analysis, DSC, UV spectra, IR spectra, NMR spectra and mass spectra. In contrast to CTX, BCTX appeared to be almost insoluble in water and its intrinsic dissolution rate was 0.183 micrograms/ml.min. The stability revealed that the degradation of BCTX suspension in water followed zero-order kinetics and the rate of degradation at room temperature was found to be 1.67 X 10(-7) mg/ml.s. An in vivo test by using 12 rabbits given BCTX suspension and CTX solution intramuscularly was conducted. The results showed that the former was longer in maintaining serum drug level than the latter.

Animals↗
PubMed1989

[Research on predicting neonatal acid-base status].

Intrapartum monitoring and umbilical arterial blood pH study were carried out in 103 cases of normal pregnancy from March 1987 to December 1987. A stepwise linear regression analysis was done on 23 factors concerning the status of the newborns and 5 significant umbilical arterial blood pH, related ones that is fetal scalp blood pH, duration of the second stage of labour. Maternal blood PCO2, BB and M/F delta BDHb5. It is considered that Fischer's FHR-monitoring scoring system M/F delta pH and status of amniotic fluid etc, bear no relation to umbilical arterial blood pH. From these 5 significant factors, a regression equation was obtained so that the acid-base status of newborns can be predicted.

Acid-Base Imbalance↗
PubMed1989

[Study on the hygienic standard of furniture for preschool children].

Fourteen anthropometric measurements of 1341 children (aged 1-7 yrs.) were cross-sectionally studied between May and August 1985 in six typical kindergartens in Harbin. Based on the data gained in the study and observation of their posture when children were using chairs and desks, the hygienic standard of furniture for preschool children is suggested. The 14 anthropometric measurements could be used as references for the designs of furniture for preschool children.

Anthropometry↗
PubMed1986

Cytochalasin B changes the cytoskeletal organization in Newcastle disease virus-infected cells.

The microfilament structures of Newcastle disease virus (NDV)-infected BHK-21 cells were studied in the presence (5 micrograms/ml) or absence of cytochalasin B (CB) by means of phase contrast, indirect immunofluorescence and thin-section immunoelectron microscopy. The results indicated that CB treatment not only impaired virus infections titers and antiactin fluorescence strength but also disrupted cytoplasmic membrane and untagged ferritin-conjugated antibody on the surface of NDV specific antigens.

Actins↗