Effects of epidermal growth factor and/or nerve growth factor on Malassez's epithelial rest cells in vitro: expression of mRNA for osteopontin, bone morphogenetic protein 2 and vascular endothelial growth factor.

BACKGROUND AND OBJECTIVE: Malassez's epithelial rest (MER) cells are involved in the maintenance and homeostasis of the periodontal ligament (PDL). The purpose of this study was to determine the effects of epidermal growth factor (EGF) and/or nerve growth factor (NGF) in vitro on these functions of MER cells. MATERIAL AND METHODS: MER cells from porcine PDL were incubated for 3 or 9 h after the addition of EGF and/or NGF to final concentrations of 10 ng/mL. Cells cultured without those growth factors were used as controls. The expression of mRNA for osteopontin, bone morphogenetic protein 2 (BMP-2) and vascular endothelial growth factor (VEGF) was analyzed using quantitative RT-PCR. RESULTS: There was a decrease in the expression of osteopontin mRNA by MER cells treated for 9 h with NGF and the level of mRNA expressed was lower than that of the control and EGF-treated groups. The expression of BMP-2 mRNA by MER cells treated with NGF for 9 h also decreased, and was lower than that of the control and EGF-treated groups. The expression of VEGF mRNA by MER cells treated with EGF for 3 or 9 h was higher than in the control and NGF-treated groups. The expression of VEGF mRNA was lower in MER cells treated with NGF for 3 and 9 h than in the control and EGF-treated groups, and decreased from 3 to 9 h of treatment. EGF stimulated MER cells to secrete VEGF, which suggests that EGF plays an important role in maintaining the homeostasis of the PDL. NGF acts on MER cells to inhibit calcification in the PDL. Furthermore, in the EGF+NGF-treated MER cells, expression of mRNA for BMP-2 and VEGF was similar to that of the NGF-treated group, but cell proliferation and expression of osteopontin mRNA were similar to that of the EGF-treated group. CONCLUSION: EGF and NGF play important roles in maintaining the PDL.

Vector manifestation of chiral symmetry.

We propose "vector manifestation" (VM) of the Wigner realization of chiral symmetry in which the symmetry is restored at the critical point by the massless degenerate pion (and its flavor partners) and the rho meson (and its flavor partners) as the chiral partner, in sharp contrast to the traditional manifestation á la the linear sigma model where the symmetry is restored by the degenerate pion and the scalar meson. The application to the chiral phase transition of large N(f) QCD is performed using the hidden local symmetry Lagrangian. Combined with the Wilsonian matching proposed recently, VM determines the critical number of massless flavors N(f) approximately equal to 5 without much ambiguity.

Fate of vector dominance in effective field theory.

We reveal the full phase structure of the effective field theory for QCD, based on hidden local symmetry (HLS) through the one-loop renormalization group equation including quadratic divergences. We then show that vector dominance (VD) is not a sacred discipline of the effective field theory but rather an accidental phenomenon peculiar to three-flavored QCD. In particular, the chiral symmetry restoration in the HLS model takes place in a wide phase boundary surface, on which the VD is nowhere realized. This suggests that VD may not be valid for chiral symmetry restoration in hot and/or dense QCD.

Valence-difference contrast measurements utilizing X-ray anomalous scattering.

Anomalous scattering experiments with X-ray wavelengths close to an absorption edge have made it possible to determine independently the behaviour of ions in different valence states. The anomalous scattering factors of Fe(2+) and Fe(3+) obtained from both absorption and diffraction data have a large difference in f' between the two kinds of ions. Using a valence-difference contrast method, Bragg and diffuse scattering measurements were carried out for single crystals of Fe(3)O(4) at low temperatures. The results demonstrate the ability of the contrast method to resolve charge ordering and valence fluctuation details.

Generation of hydrogen peroxide by varicella-zoster virus-stimulated polymorphonuclear leukocytes.

BACKGROUND: In varicella-zoster virus (VZV) infections, the initial response in cutaneous lesions is predominantly polymorphonuclear leukocytes (PMN). However, interaction of VZV and PMN has not yet been fully defined. OBJECTIVES: To explore the potential role of PMN in VZV infections, we investigated the ability of PMN to generate hydrogen peroxide (H(2)O(2)) after stimulation with VZV antigen. STUDY DESIGN: H(2)O(2), one of the reactive oxygen species, was measured by cytofluorography after PMN were incubated with varicella-zoster virus (VZV) antigen in the presence of seropositive or seronegative serum. RESULTS: H(2)O(2) was detectable in unseparated PMN obtained from seropositive children and adults, while unseparated PMN of seronegative donors were not capable of generating H(2)O(2). Separated PMN obtained from either seropositive or seronegative donors were capable of generating H(2)O(2) in the presence of seropositive serum. However, H(2)O(2) was not detectable in separated PMN of seropositive donors in the presence of seronegative serum. The of H(2)O(2) generation did not correlate with concentrations of serum antibodies to VZV. CONCLUSIONS: VZV antigen-antibody complexes might induce H(2)O(2) generation by PMN.

Differential expression of genes involved in the biosynthesis and perception of ethylene during ripening of passion fruit (Passiflora edulis Sims).

An increase in the enzyme activity of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase and ACC oxidase induces the evolution of ethylene during the ripening of passion fruit. A much higher level of ethylene is produced in arils than in seeds or peels during ripening. The pattern of expression of two ACC synthase genes (PE-ACS1 and PE-ACS2), one ACC oxidase gene (PE-ACO1), and two ethylene receptor genes (PE-ETR1 and PE-ERS1) revealed that the expression of these genes is differentially regulated. Expression of PE-ACS1 and PE-ACO1 was enhanced during ripening and after ethylene treatment. However, prominent expression of PE-ACS1 was delayed compared to that of PE-ACO1. Much larger quantities of PE-ACS1 mRNA and PE-ACO1 mRNA were seen in arils than in seeds; this corresponds well with an increase in the amount of ethylene produced by the plant tissue itself. The level of PE-ACS2 mRNA was detectable in arils of the preclimacteric fruit, although it decreased during ripening. These results suggest that expression of PE-ACS1 and PE-ACO1 is required to increase the activity of ethylene biosynthetic enzymes during ripening. The level of expression of PE-ETR1 and PE-ERS1 did not significantly change over the course of ripening; however, the mRNA levels of PE-ETR1 and PE-ERS1 were much higher in arils than in seeds.

Effect of varicella zoster virus antigen-antibody complexes on hydrogen peroxide generation by human polymorphonuclear leukocytes.

Hydrogen peroxide (H2O2) generation by human polymorphonuclear leukocytes (PMN) incubated with varicella zoster virus (VZV) antigen was studied by cytofluorography. Hydrogen peroxide generation was detected in the presence of VZV-seropositive sera. When seropositive sera were heat-inactivated, H2O2 generation was reduced. When PMN were pre-incubated with Leu-11b, a monoclonal antibody to the Fc receptor on PMN, H2O2 generation was also reduced. These results suggest that VZV antigen-antibody-complement complexes induce H2O2 generation by PMN after these complexes attach to Fc receptors on PMN.

A flow cytometric method for measurement of hydrogen peroxide generation by pediatric polymorphonuclear leukocytes stimulated by Staphylococcus aureus and Escherichia coli.

The generation of hydrogen peroxide (H2O2), one of the reactive oxygen species, by polymorphonuclear leukocytes (PMN) stimulated by Staphylococcus aureus and Escherichia coli was studied in infants by cytofluorography. After heparinized whole blood was incubated with bacteria for 60 min, generated H2O2 was measured. The positive rate of H2O2 generation of PMN and mean fluorescent intensity of positive PMN stimulated by S. aureus and E. coli were significantly reduced in infants aged < 1 year and H2O2 generation increased with advancing age. In 10-15 year old children, the level of generated H2O2 reached adult levels. When sera from 1 year old children were added to separated PMN from healthy adults, H2O2 generation was reduced. In contrast, H2O2 generation by PMN from 1 year old children was increased by the addition of adult sera. These results suggest that the ability to generate H2O2 in response to S. aureus and E. coli is lower in infants and that such reduced activity may be related to the susceptibility of such infants to S. aureus and E. coli infections.

Identification of human CPI-17, an inhibitory phosphoprotein for myosin phosphatase.

CPI-17 is a phosphorylation-dependent inhibitor of myosin phosphatase. cDNA clones encoding CPI-17 were isolated from a human aorta library. Overlapping clones indicated two isoforms: CPI-17alpha was 147 residues and mass of 16.7 kDa; CPI-17beta (120 residues, mass 13.5 kDa) resulted from a deletion in the alpha-isoform of 27 residues, sequence 68-94. N-terminal 67 residues of all CPI-17 isoforms (human, porcine, rat and mouse) were highly conserved (for the human and porcine isoforms the identity was 91%). The presence of the two human isoforms was detected from cDNA sequences amplified by RT-PCR and by Western blots on human aorta. The cloned human CPI-17 gene indicated 4 coding exons and CPI-17beta was an alternative splice variant due to deletion of the second exon. FISH analysis located the human CPI-17 gene on chromosome 19q13.1.