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Biomedical subjects

C Fan

Publications and source records attributed to C Fan.

At least 91 records · Page 5Linked to original sources
PubMed1996

Effect of chronic oral moricizine and intravenous epinephrine on ventricular fibrillation and defibrillation thresholds.

The purpose of this study was to determine the effects of chronic oral moricizine therapy and physiological doses of epinephrine on ventricular fibrillation and defibrillation thresholds using an implantable transvenous/subcutaneous defibrillation system in a pig model. Thirteen pigs completed the three phases of the study. After a baseline study on day 1, the animals were randomized to receive moricizine 10-15 mg/kg tid or placebo for seven doses, at which time the protocol was repeated on day 4. The same protocol was again repeated on the same day after infusion of physiological doses of epinephrine. Multiple ventricular fibrillation and defibrillation thresholds were measured during each study. Moricizine did not alter ventricular fibrillation nor defibrillation thresholds, whereas epinephrine increased the ventricular defibrillation threshold from 20.8 J to 23.7 J (P < 0.05). In addition, we observed an increase in both ventricular fibrillation (19.7 J vs 12.6 J; P < 0.05) and defibrillation (20.8 J vs 17.8 J; P 0.05) thresholds over the 4 days of the study. These findings suggest that moricizine may be a safe antiarrhythmic agent to use in patients with implantable cardioverter defibrillators, and that elevated endogenous epinephrine may render defibrillation more difficult.

Administration, Oral↗
PubMed1995

A common fold for peptide synthetases cleaving ATP to ADP: glutathione synthetase and D-alanine:d-alanine ligase of Escherichia coli.

Examination of x-ray crystallographic structures shows the tertiary structure of D-alanine:D-alanine ligase (EC 6.3.2.4). a bacterial cell wall synthesizing enzyme, is similar to that of glutathione synthetase (EC 6.32.3) despite low sequence homology. Both Escherichia coli enzymes, which convert ATP to ADP during ligation to produce peptide products, are made of three domains, each folded around a 4-to 6-stranded beta-sheet core. Sandwiched between the beta-sheets of the C-terminal and central domains of each enzyme is a nonclassical ATP-binding site that contains a common set of spatially equivalent amino acids. In each enzyme, two loops are proposed to exhibit a required flexibility that allows entry of ATP and substrates, provides protection of the acylphosphate intermediate and tetrahedral adduct from hydrolysis during catalysis, and then permits release of products.

Adenosine Diphosphate↗
PubMed1995

Synergistic interaction between ORM1 and C3 types in disease associations.

In previous studies of orosomucoid (ORM) types and disease the ORM1 1 type has been found to be associated with sarcoidosis and other immunogenetic diseases, and the ORM 1 2 type with different types of carcinomas. We report significant associations between ORM1 and C3 types in sarcoidosis and breast cancer, but not in healthy individuals. The ORM1 1 and C3S variants in combination increased the risk of sarcoidosis, and the ORM1 2 and C3F variants together gave an increased risk of breast cancer. A probable mechanism may be that the ORM1 and C3 molecules modify the immune response by interacting with the lymphoid cell surface.

Alleles↗
PubMed1995

Orosomucoid and haptoglobin types in patients with sarcoidosis.

Association with HLA and complement factors has been reported in sarcoidosis, and the results of previous studies suggest a multifactorial and immunogenetic etiology of the disease. We have studied two genetic acute-phase reactant systems, orosomucoid (ORM) and haptoglobin (HP), in 226 patients with sarcoidosis and population controls from northern Sweden. Significant allele and phenotype differences between patients and controls were found in both systems. The ORM1 phenotype showed a significant increase in sarcoidosis (RR = 1.34, p = 0.036), which was more pronounced among patients with low (< 1,500 nkat/l) angiotensin-converting enzyme levels (RR = 1.83, p = 0.00065) and hypercalcemia (RR = 3.69, p = 0.0023). The HP1 type was significantly increased among the sarcoidosis patients (RR = 1.57, p = 0.013). The results suggest that the ORM1 1 and HP1 types may be contributory determinants in the multifactorial etiology of sarcoidosis.

Female↗
PubMed1995

[Molecular cloning of cellulase gene from the bacillus].

The CMCase gene from the Bacillus sp. strain E2 was cloned into E. coli DH5 alpha F' using plasmid pBR322 as a vector. Recombinant plasmid pBG3 was isolated from transformants producing CMCase, and the cloned CMCase gene was found to be in a 4.0kb HindIII fragment. The CMCase gene was subcloned in a functional state on a 2.4kb DNA fragment. The optimum pH and temperature for activity of CMCase encoded by pBG3 were pH 6.5 and 55 degrees C respectively. The CMCase could not hydrolyze any natural cellulose examined. Eighty-three percent of the CMCase was detected in the inner cellular fraction, 9% and 8% were in the periplasmic space and medium respectively. Result of Southern hybridization indicates that the cloned DNA fragment was derived from Bacillus sp. strain E2 chromosomal DNA.

Bacillus↗
PubMed1994

Vancomycin resistance: structure of D-alanine:D-alanine ligase at 2.3 A resolution.

The molecular structure of the D-alanine:D-alanine ligase of the ddlB gene of Escherichia coli, co-crystallized with an S,R-methylphosphinate and adenosine triphosphate, was determined by x-ray diffraction to a resolution of 2.3 angstroms. A catalytic mechanism for the ligation of two D-alanine substrates is proposed in which a helix dipole and a hydrogen-bonded triad of tyrosine, serine, and glutamic acid assist binding and deprotonation steps. From sequence comparison, it is proposed that a different triad exists in a recently discovered D-alanine:D-lactate ligase (VanA) present in vancomycin-resistant enterococci. A molecular mechanism for the altered specificity of VanA is suggested.

Adenosine Diphosphate↗
PubMed1994

An upstream region of the enoyl-coenzyme A hydratase/3-hydroxyacyl-coenzyme A dehydrogenase gene directs luciferase expression in liver in response to peroxisome proliferators in transgenic mice.

Peroxisome proliferators, which are structurally diverse nonmutagenic agents, induce hepatocarcinogenesis in rats and mice. Exposure to these xenobiotics leads to a rapid and coordinated transcriptional activation of the genes for the peroxisomal beta-oxidation enzyme system pathway in the liver. We have previously identified a peroxisome proliferator-responsive element in the 5'-flanking region of the rat peroxisomal hydratase/dehydrogenase (PBE) gene, the second enzyme in the beta-oxidation pathway. The peroxisome proliferator-responsive element in the PBE gene was shown to direct the induction of a luciferase reporter gene in vitro. We have now used this 3.2-kilobase 5'-flanking region of the PBE gene fused to the coding region of luciferase to generate transgenic mice. Three independent lines of transgenic mice expressed luciferase in response to ciprofibrate, a peroxisome proliferator. The induction of luciferase is specific to the liver; this agrees with the tissue-specific induction of PBE. Two other hypolipidemic drugs, nafenopin and Wy-14,643, were also capable of inducing luciferase activity in the liver. This study suggests that the PBE upstream element can be used to direct and modulate the expression of cloned genes by changing the levels of peroxisome proliferators. Also, the PBE-luciferase transgenic mouse should be an excellent model system for screening xenobiotics for potential peroxisome proliferator property.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1994

Comparison of personality traits of only and sibling school children in Beijing.

The number of only children in China has increased rapidly since the late 1970s, when the Chinese government advocated the "one-child-per-family" policy. This increase has caused much public concern about the healthy growth of the young generation. In this study the behavioral traits of Chinese, urban, only children were investigated. The participants were 444 children with siblings and 473 only children from Grades 1, 3, and 5 in Beijing primary schools. An inventory consisting of 27 items covering three behavioral traits was developed. The children were rated on the inventory by the principal teacher of the class. Factor analysis revealed three main factors: achievement motivation, interpersonal skills, and attitude toward manual labor. The only children exceeded the sibling children on achievement motivation. No differences were found between only children and sibling children on interpersonal skills and attitude toward manual labor. Gender differences were evident; girls consistently received higher ratings on achievement motivation and interpersonal skills. The possible underlying reasons for these differences are discussed.

Achievement↗