Interobserver variation in the reporting of cervical colposcopic biopsy specimens: comparison of grading systems

AIMS: To assess interobserver variation in reporting cervical colposcopic biopsy specimens and to determine whether a modified Bethesda grading system results in better interobserver agreement than the traditional cervical intraepithelial neoplasia (CIN) grading system. METHODS: One hundred and twenty five consecutive cervical colposcopic biopsy specimens were assessed independently by six histopathologists. Specimens were classified using the traditional CIN grading system as normal, koilocytosis, CIN I, CIN II, or CIN III. The specimens were also classified using a modified Bethesda grading system as either normal, low grade squamous intraepithelial lesion (LSIL) or high grade squamous intraepithelial lesion (HSIL). Participants were also asked to categorise biopsy specimens by the CIN system with the addition of the recently proposed category "basal abnormalities of uncertain significance (BAUS)". The degree of agreement between participants was assessed by kappa statistics. RESULTS: Using the CIN system, interobserver agreement was generally poor: unweighted and weighted kappa values between individual pairs of observers ranging from 0.05 to 0.34 (average 0.20) and from 0.20 to 0.54 (average 0.36), respectively. With the modified Bethesda system, interobserver agreement was better but still poor: unweighted and weighted kappa values ranging from 0.15 to 0.58 (average 0.30) and from 0.21 to 0.61 (average 0.36), respectively. There was little or no agreement between observers in the diagnosis of BAUS. CONCLUSIONS: Interobserver agreement in the reporting of cervical colposcopic biopsy specimens using the CIN grading system is poor. Agreement, while still poor, is better when a modified Bethesda grading system is used. There is little or no consensus in the diagnosis of BAUS.     

Product specificity of rice germ lipoxygenase

Incubation of linoleic acid with partially purified lipoxygenase from rice germ yielded a ratio of 9-to 13-hydroperoxides of linoleic acid of 97∶3 as measured by high performance liquid chromatography. Under similar conditions, hematin gave the 9- to 13-hydroperoxides at a ratio of 51∶49, and soybean lipoxygenase-a at 9∶91. Infrared spectral analysis revealedcis-trans configuration to predominate in the reaction products with the rice germ enzyme as was with the soybean enzyme.     

Numerical analysis of three-parallel embedded optical waveguides

Three parallel embedded dielectric waveguides are investigated numerically. The mode-matching method that matches the boundary conditions in the sense of least squares is applied to this problem, using the hybrid-modal representation. Precise numerical results for the dispersion relations and field distributions are presented for the lowest three modes near the cutoff. The frequency range in which only the three modes can propagate and the differences in their propagation constants are discussed at length, in order to highlight the available frequency range and the coupling length of the configuration with respect to its use as a directional coupler     

Novel route of synthesis of Mn---Mg---ferrites using stabilised MnO

Stoichiometric polycrystalline samples of Mn_xMg_1−xFe₂O₄ (0·5 ≤ x ≤ 0·66) have been synthesized by following a novel route using stabilized MnO and Fe₂O₃ at high temperatures. This route precludes the formation of large amounts of Mn³⁺ and Fe²⁺ and precipitation of MgO and -Fe₂O₃ which are generally observed during the usual route of preparation by conventional ceramic techniques. These samples have been characterized for their structural and magnetic properties using X-ray diffraction, Fe⁵⁷ Mössbauer spectroscopy and bulk magnetic properties such as initial permeability, loss factor, ferromagnetic transition temperature, remanance and coercivity. For X = 0·62, these ferrites exhibit the highest remanance ratio 0·96, suitable for square loop applications.