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Biomedical subjects

C Wei

Publications and source records attributed to C Wei.

At least 109 records · Page 6Linked to original sources
PubMed1996

Genetic expression of endothelial nitric oxide synthase in human atrial myocardium.

OBJECTIVE: To investigate the expression of endothelial nitric oxide synthase (eNOS) in human cardiac tissues. DESIGN: We attempted to determine the genetic expression and localization of eNOS in normal human atrial tissue. MATERIAL AND METHODS: In normal human right atrial tissues from five donors during cardiac transplantation, eNOS expression and localization were assessed by using Northern blot analysis, in situ hybridization, and immunohistochemical staining. RESULTS: Northern blot analysis and in situ hybridization demonstrated that eNOS messenger RNA is present in cardiomyocytes. Positive immunohistochemical staining was observed in the cytoplasm of cardiomyocytes. CONCLUSION: These studies show for the first time the genetic expression and distribution of eNOS in human atrial myocardium and suggest that the eNOS mediated paracrine and autocrine pathway may participate in the control of myocardial function in humans.

Base Sequence↗
PubMed1996

Synthesis and application of novel nucleoside phosphonates and phosphoramidites modified at the base moiety.

The H-phosphonates and phosphoramidites of 2'-deoxyisoguanosine, 2'-deoxyisoinosine, 5-aza-7-deaza-2'-deoxyguanosine, and N1-methyl-2'-deoxyformycin A were prepared. The diphenylcarbamoyl group was chosen for the 2-O-protection of 2'-deoxyisoinosine and 2'-deoxyisoguanosine, and dimethylaminoalkylidene groups were used to block the amino function of the various monomers. The synthesis of isoguanine oligonucleotides was found to be much more efficient using the 2-O-protected building blocks compared to those without oxygen protection. Oligodeoxynucleotides containing 2'-deoxyisoguanosine and 2'-deoxycytidine form parallel duplex structures. The self-complementary duplex containing 5-aza-7-deaza-2'-deoxyguanosine and 2'-deoxycytidine forms a stable duplex in acidic solution (pH = 5.0) while it is destabilized under neutral conditions.

Amides↗
PubMed1996

Immunodetection of beet necrotic yellow vein virus RNA3-encoded protein in different host plants and tissues.

The protein p25 open reading frame (ORF) of beet necrotic yellow vein virus-BNYVV RNA3 was cloned into bacterial expression vector downstream of the 5-'terminus part of beta-galactosidase ORF and the expressed p25 fusion protein was used to produce an antiserum. The latter was employed to detect the subcellular location of p25 in mechanically inoculated Tetragonia expansa, Chenopodium quinoa and sugarbeet leaves by Western blot assay. The results showed that p25 was present as a soluble protein only in the S30 fraction of T. expansa, C. quinoa and sugarbeet leaves infected with BNYVV.

Animals↗
PubMed1996

[The clinical efficacy of hepatic artery infusion chemotherapy and chemoembolization in the treatment of liver metastases].

The efficacy and clinical experience of transcatheter hepatic artery infusion chemotherapy alone or chemoembolization in 118 patients with hepatic metastases were reviewed. Hepatic arterial infusion chemotherapy followed by embolization with lipiodol suspension and gelatin sponge pieces was carried out in 72 cases, infusion chemotherapy followed by embolization with lipiodol suspension in 32, and arterial infusion chemotherapy alone in 14. The results showed that the clinical efficacy of the first method was the best while that of the third method was the worst. The best effect was seen in patients with the single and hypervascular metastatic focus. The overall survival rate was 86.0%, 25.0%, 3.0% in 1 year, 3 years and 5 years, respectively.

Antineoplastic Agents↗
PubMed1995

Comparison of branched-chain and tightly coupled reaction mechanisms for prostaglandin H synthase.

Two types of mechanisms have been proposed to account for the combination of peroxidase and cyclooxygenase activities in prostaglandin H synthase (PGHS). One, a branched-chain mechanism [Dietz, R., et al. (1988) Eur. J. Biochem. 171, 321-328], postulates that the cyclooxygenase reaction propagates essentially independently of peroxidase catalysis. The second, a tightly coupled mechanism [Bakovic, M., & Dunford, H. B. (1994) Biochemistry 33, 6475-6482], postulates that peroxidase catalysis is an integral part of cyclooxygenase propagation. Qualitative and quantitative predictions from the two mechanisms have been compared with several observed characteristics of the PGHS reaction with arachidonate, including the ability to accumulate PGG2 and oxidized enzyme intermediates, the stoichiometry between cosubstrate and fatty acid consumption, and the hydroperoxide activator requirement. The observed characteristics, particularly the accumulation of micromolar levels of PGG2 even in the presence of cosubstrate and the stoichiometry between cosubstrate oxidation and fatty acid oxygenation of less than 1.3 (compared to a theoretical maximum of 2.0), were largely consistent with predictions from the branched-chain mechanism, but contradicted important predictions of the tightly coupled mechanism. These results indicate that PGHS catalysis is more accurately described by the branched-chain mechanism than by the tightly coupled mechanism.

Animals↗
PubMed1995

Intraoperative laparoscopic diagnosis of contralateral patent processus vaginalis in children with unilateral inguinal hernia.

The contralateral internal ring of 96 children was examined laparoscopically during unilateral hernia repair to minimize the chance of development of contralateral hernia. Laparoscopy was performed through the hernia sac before ligation. Of 29 patients with positive laparoscopic findings, 28 had a patient processus vaginalis as confirmed by simultaneous contralateral exploration and there was one false positive. Patency of the contralateral processus vaginalis was found in 28 (29 per cent) of the 96 patients. Children under 2 years of age had a significantly higher incidence of patent contralateral processus vaginalis than older patients. The only complication of the procedure was wound infection in two patients. This is a simple, safe and accurate procedure to select children for contralateral surgical exploration.

Age Distribution↗
PubMed1995

The application of segment axial density profiles to a human body inertia model.

The intention of this study was to construct segment density profiles and compare segment inertias calculated when uniform densities and profile densities are used in a mathematical model. Axial densities from computerized tomography (CT) slices for the body segments of a sample of Chinese females (Zheng et al., Proceedings of the Beijing Asian Games Scientific Congress, 1990) were used to form profiles which could be employed in body segment models. Polynomials based on proportion of segment length were fitted to the reported mean slice densities. These profiles were then used with five widely divergent samples (n = 10); young adult females, young adult males, infants, male children and elderly adults. The mathematical model used is based on an assumption that all segments can be represented by stacked elliptic cylinders. The results show that when the profile densities were substituted for average cadaver densities the increase in the estimated total body mass was less than 0.85%. For the individual segments, use of the profile rather than average density increased the average segment mass estimate by up to 2.7%. The centres of mass and the principal moments were affected by the variations in density along the axis as well as the magnitudes, by up to 0.54 and 3.8%, respectively. Although the effects of using the profiles appear to be small the differences for individual samples, segments and parameters ranged up to 22.5%. It is not possible to decide if average or profile densities produce more accurate estimates of inertia, but the profile allows for axial variation in density and is therefore recommended.

Adolescent↗
PubMed1995

The morphology of the contralateral internal inguinal rings is age-dependent in children with unilateral inguinal hernia.

The contralateral internal inguinal rings of 333 children were examined with a laparoscope during repair of unilateral inguinal hernia. The nonpuncture laparoscopy technique was used so that no extra wound was created. The morphology of the rings was classified as follows: type 1, flat and covered tightly with peritoneum; type 2, shallow with a visible base under an elevated peritoneal fold; type 3, deep ring that represented a patent processus vaginalis. The incidence of types 1, 2, and 3 rings was 45%, 23%, and 32%, respectively. The incidence of type 1 internal rings was similar for different age groups. The incidence of type 2 rings increased with age, and that of type 3 decreased with age. This observation is compatible with autopsy studies and the experience of contralateral exploration of childhood inguinal hernias.

Adolescent↗
PubMed1995

Epipolarization microscopic immunogold assay: a combination of immunogold silver staining, enzyme-linked-immunosorbent assay and epipolarization microscopy.

We describe a new immunoassay which combines an immunosorbent assay, immunogold silver staining and epipolarization microscopy. Our new assay procedure features multiple samples on a single microscope slide, and high sensitivity of epipolarization microscope for detection of silver-enhanced colloidal gold as a final immunoassay product. We call the new immunoassay "on slide immunogold assay" (OSIGA). This new method uses biotinylated antibody and streptavidin-gold reaction with silver enhancement technique. With OSIGA it is possible to investigate 30 samples on a single microscopic slide. Our preliminary studies used 10-20 microliter samples and detected nanogram quantities of a standardized protein solution. Unlike enzyme linked immunosorbent assay (ELISA), which has a limited time for reading the final color products, the OSIGA specimens can be dried or resin mounted for longer storage and future reference.

Animals↗
PubMed1994

DNA analysis of an uncommon missense mutation in a Gaucher disease patient of Jewish-Polish-Russian descent.

Gaucher disease is the most frequent lysosomal lipid storage disease. It results from deficient glucocerebrosidase activity and is transmitted as an autosomal recessive trait. Three clinical forms of Gaucher disease have been described: type 1, non-neuronopathic; type 2, acute neuronopathic; and type 3, subacute neuronopathic. We have sequenced the full length cDNA of the glucocerebrosidase gene and identified an uncommon mutation in nucleotide position 1604 (genomic DNA nucleotide position 6683) from a Gaucher disease patient of Jewish-Polish-Russian descent with type 1 Gaucher disease. It is a G-->A transition in exon 11 that results in 496Arg-->496His of glucocerebrosidase. This missense mutation is present in the heterozygous form and creates a new cleavage site for the endonuclease HphI. We have developed a simple method to detect the presence of this mutation by using HphI restriction fragment length polymorphism analysis of glucocerebrosidase genomic DNA or cDNA. The mutation in the other Gaucher allele of this patient is an A-->G transition at cDNA nucleotide position 1226 which creates an XhoI cleavage site after PCR mismatch amplification. The presence of this mutation was also confirmed by sequence analysis. Based on previous reports that mutation 1226 is present only in type 1 Gaucher disease and the observation that there is no neurological involvement in this patient, we conclude that our patient with the 1226/1604 genotype is diagnosed as having type 1 Gaucher disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Development of a lambda-based complementation assay for the preliminary localization of lacI mutants from the Big Blue mouse: implications for a DNA-sequencing strategy.

The Big Blue transgenic mouse carrying the E. coli lacI gene as a mutational target in a lambda-based shuttle vector has been receiving increasing attention in genotoxicity testing because it offers the potential of studying mutation in a mammalian system in vivo. The system not only provides information on mutant frequency, but it also offers the potential of providing information about mutational specificity. Such data is not only important for studies of mutational mechanisms; it offers a critical advantage for determining the mutational response at levels where significant increases in mutant frequency have not been discerned. The repeated sequencing of the entire 1080-bp lacI target, however, remains a formidable task. Here we report on the adaptation of the "negative complementation" assay for the lacI-d phenotype to accommodate the lambda lacI recovered from the Big Blue transgenic animal. This assay permits the localization of mutations to an approximately 330-bp region to facilitate the production of mutational specificity data. The assay is based upon lysogenization of the lambda containing the lacI mutation into a lacI+ host. Of 107 sequenced lacI mutants recovered from Big Blue mice, 74 were identified as NC+ (lacI-d) using this assay. Of these 74, 49 occurred in the region 32-208 bp, which has traditionally been viewed as the NC+ domain. 33 of these mutations were previously identified as producing the NC+ phenotype while another 7 occurred at sites where NC+ mutants have been recovered, but involved a new base substitution. 9 mutants involved new sites. An additional 25 mutants located downstream of the presumed NC+ region were also found to be NC+ as determined by their blue colour on X-gal plates. Of these, 18 occurred in the 209-360-bp region. In parallel, 54 lacI mutants carrying unknown mutations were examined. 37 of these produced blue colonies in this assay. The sequencing of these mutants revealed that 20 (54%) of the 37 mutants were located in the 32-208-bp region. This complementation assay can potentially reduce the amount of DNA sequencing necessary to produce a mutational spectrum by optimising the choice of sequencing primers, and thus provide a significant saving of the material and time required. Furthermore, evidence indicates that the restriction of the mutational target to the NC+ region extends these savings without reducing the usefulness of the mutational specificity data.

Amino Acid Sequence↗
PubMed1994

Inhibition of bacterial enzyme activity and luminescence by urban river sediments.

The toxicological and ecological effects of pollutants in urban river sediments were studied. The sediments were chemically or physically fractionated, using selective extractants to separate the effects of metal and organic contaminants, and subsequently tested for the inhibition of bacterial enzyme activity and luminescence. In many cases the enzyme activity of the sediment-dwelling bacteria was inhibited by metals. The variations in inhibition were attributed to differences in sediment complexation of, rather than bacterial community tolerance to, metals. Non-polar organic compounds significantly increased the toxicity of urban river sediments, and it is proposed that polyaromatic hydrocarbons from storm-water are an important source of sediment toxicity.

Fresh Water↗