Mutations of ras oncogenes in 37 human stomach cancers and 13 adenomas were investigated with regard to the histological phenotypes using polymerase chain reaction (PCR), allele‐specific oligonucleotide hybridization and/or direct sequencing of the PCR products. The ras mutation was found only in one case (2.7%), the histology of which was poorly differentiated adenocarcinoma. We found no mutation in stomach adenomas. The mutation consisted of a guanine‐to‐adenine transition in the first base of codon 13 of c‐Ki‐ ras which replaced wild‐type glycine with serine, indicating that a putative glycine‐to‐aspartic acid change is not necessarily the critical event for c‐Ki‐ ras gene activation in codon 13. These results further confirm the infrequency of ras mutation in stomach tumors and also suggest that ras mutations are not specific to the differentiated type of stomach cancer.
An analytical wave-optics solution is derived for the modal structure of the Čerenkov second-harmonic optical field in weakly guiding cylindrical fiber waveguides. Numerical results for the axially symmetric mode indicate that the second-harmonic power significantly depends on the dimension of the core.
The apoptotic effect of adenosine and its analogues was studied in fibroblast‐like synoviocytes derived from rheumatoid arthritis patients (RA‐FLSs). Evoked cell death was quantitatively examined by assessing DNA fragmentation using an enzyme‐liked immunosorbent assay and by measuring phosphatidylserine exposure through flow cytometric analysis of annexin V binding. Exposing cells for 24 h to 2‐chloroadenosine (2‐CADO), a nonspecific, adenosine deaminase (ADA)‐resistant, adenosine receptor (AdoR) agonist, induced DNA fragmentation, and thus apoptosis, in RA‐FLSs at concentrations 50 μ M . By contrast, incubation with adenosine for up to 72 h did not evoke DNA fragmentation, even in the presence of ADA inhibitor coformycin and nucleoside transporter inhibitor nitrobenzylmercaptopurin (NBMPR). Transcription of all four AdoR isoforms was detected in RA‐FLSs; nevertheless selective AdoR agonists similarly failed to induce DNA fragmentation. DNA fragmentation evoked by 2‐CADO was inhibited by NBMPR and by 5′‐iodotubercidin, an adenosine kinase inhibitor, but not by xanthine amine congener, an A 1 and A 2 receptor antagonist, or by selective AdoR antagonists. The nonspecific caspase inhibitor benzyloxycarbonyl‐Val‐Ala‐Asp fluoromethyl ketone abolished the apoptotic effect of 2‐CADO. These results suggest that 2‐CADO induces apoptosis in RA‐FLSs independently of AdoR‐mediated signalling. Instead, 2‐CADO, but not adenosine, is taken up into RA‐FLSs via human equilibrative nucleoside transporter‐1, where it is phosphorylated by adenosine kinase. The resultant phospho‐2‐CADO induces DNA fragmentation by activating a caspase pathway. British Journal of Pharmacology (2002) 135 , 1477–1486; doi: 10.1038/sj.bjp.0704612
A vector finite-element method for the analysis of anisotropic waveguides with off-diagonal elements in the permeability tensor is formulated in terms of all three components of the electric field. In this approach, spurious, nonphysical solutions do not appear anywhere above the "air-line." The application of this finite-element method to waveguides with an abrupt discontinuity in the permittivity is discussed. In particular, we discuss how to use the boundary conditions of the electic field at the interface between two media with different permittivities. To show the validity and usefulness of this formulation, examples are computed for dielectric-loaded waveguides and ferrite-loaded waveguides.
A new vectorial finite-element method for the analysis of dielectric waveguide problems is formulated in terms of all three components of the magnetic field H. In this approach, the relation div H = 0 is satisfied and the spurious non-physical solutions do not appear.
An efficient finite-element approach for the eigenmode analysis of unbounded guided-wave problems is described using decay-type infinite elements. To determine an optimum set of decay parameters, two algorithms based on successive approximation are presented and their validity is checked by application to an optical fiber problem.< >
A new design of multicore photonic crystal fibers (PCFs) is proposed and investigated through full-vectorial finite-element method and finite-element beam propagation method. The fiber design comprises four identical cores surrounding a central core. The optical power launched into the central core is equally divided into other neighboring four cores with a 25% of coupling ratio. The coupled-mode analysis is also carried out to understand the supermode patterns and the coupling characteristics. Through numerical simulations, it is demonstrated that the optical power can be divided equally in a 5.8-mm-long multicore PCF. The power coupling characteristics obtained through coupled-mode analysis are in very good agreement with those calculated from beam propagation method solver.
Abstract Background: A new enzyme immunoassay (EIA) for automated detection of antinuclear antibodies (ANAs) uses a mixture of HEp-2 cell extracts and multiple recombinant nuclear antigens immobilized on beads. We compared this EIA and an immunofluorescence (IF) assay in a large group of patients and controls. Methods: We studied 492 healthy individuals and 307 patients with connective tissue diseases (CTDs). Sera were tested by an automated EIA (COBAS® Core HEp2 ANA EIA; Roche Diagnostics) and IF. Samples were also tested for eight disease-specific antibodies, including antibodies against U1RNP, Sm, SSA/Ro, SSB/La, Scl-70, Jo-1, dsDNA, and centromere. Results: Areas under ROC curves for the EIA were greater than (P = 0.008–0.012) or numerically identical to areas for the IF method for each of six CTDs studied. ROC areas for EIA were 0.98 (95% confidence interval, 0.95–0.99), 0.99 (0.96–1.00), and 0.99 (0.98–1.00) in systemic lupus erythematosus (n = 111), systemic sclerosis (n = 39), and mixed connective tissue disease (n = 33), respectively. For all 258 CTD patients with conditions other than rheumatoid arthritis (RA), the sensitivity and specificity of the IF method at a cutoff dilution of 1:40 were 92% and 65%, respectively, vs 93% and 79% for the EIA at a cutoff of 0.6. For the IF method at a cutoff dilution of 1:160, sensitivity and specificity were 81% and 87%, respectively, vs 84% and 94%, respectively, for the EIA at a cutoff of 0.9. For 207 sera containing at least one of eight disease-specific ANAs, positivities for the EIA and the IF method were 97.1% and 97.6%, respectively, at cutoffs of 0.6 and 1:40 (P = 0.76). Conclusions: An EIA that can be performed by a fully automated instrument distinguishes CTDs (except RA) from healthy individuals with both higher sensitivity and specificity than the IF method when the cutoff index was set at 0.9. Moreover, it can be used to exclude the presence of disease-specific ANAs by setting the cutoff index at 0.6 with almost the same efficacy as the IF method.
A numerical approach based on the finite element method is described for the analysis of general three-dimensional, conical diffraction by arbitrarily profiled gratings. In order to show the validity and usefulness of this approach, the calculated conical diffraction efficiencies of groove-type dielectric gratings are presented.
