Object. It has been suggested that nuclear factor (NF)-κB, a pleiotropic transcription factor, controls cell proliferation. The authors examined NF-κB activity and its participation in the growth of human malignant astrocytoma. Methods. The authors examined NF-κB activity in human malignant astrocytoma cell lines and high-grade astrocytoma tissues by using electrophoretic mobility shift assays and immunohistochemical studies, respectively. In addition, messenger (m)RNA expression of p50 and RelA, which are representative subunits of NF-κB, and IκBα, which is a representative inhibitory protein of NF-κB, were analyzed using Northern blot hybridization in the astrocytoma cell lines. Furthermore, alterations in DNA synthesis and cell growth in the astrocytoma cell lines were examined after inhibition of NF-κB activity by RelA antisense oligodeoxynucleotide. The authors found NF-κB activity in all astrocytoma cell lines and high-grade astrocytoma tissues that were examined, but not in the fetal astrocyte strain or in normal cerebral tissue. Expression of p50, RelA, and IκBα mRNA was found in the fetal astrocyte strain and normal adult brain tissue, in addition to the astrocytoma cell lines. The relative levels of expression of these mRNAs were similar among these cell lines, the cell strain, and normal tissue. The RelA antisense oligodeoxynucleotide specifically reduced the levels of RelA mRNA expression and NF-κB activity in the astrocytoma cell lines, thus significantly inhibiting their DNA synthesis and cell growth. Conclusions. Human malignant astrocytoma cells have aberrant NF-κB activity, which promotes their growth. This activity is not associated with aberrant expression of p50 and RelA.

SYNOPSISHigh-speed bicomponent spinning of poly(ethy1ene terephthalate) (PET) (core) and polypropylene (PP) (sheath) was carried out and the structure development in the individual components, PET and PP, was investigated. The orientation and crystallinity development in the P E T component was enhanced as compared to that of the single-component spinning while the PP component remained in a low orientation state and had a pseudo-hexagonal crystal structure even at high take-up speeds. T o clarify the mutual interaction between the two components in bicomponent spinning, a semiquantitative numerical simulation was performed. The simulation results obtained using the Newtonian fluid model showed that the solidification stress in the P E T component was enhanced while that of the PP component was decreased in comparison with the corresponding single-component spinning. This is due to the difference in the temperature dependence of their elongational viscosity. Simulation with an upper-convected Maxwell model as the constitutive equation suggested that significant stress relaxation of the PP component can occur in the spinline if the PET component solidifies earlier than does PP. Based on the structural characterization results and the simulation results, it was concluded that the difference in the activation energy of the elongational viscosity and solidification temperature between the two polymers are the main factors influencing the mutual interaction in the bicomponent spinning process.

Controversy persists concerning the pathogenesis of dural arteriovenous malformations (AVM's) and whether they are congenital or acquired. Furthermore, it remains undetermined whether the lesion is located in the sinus itself or within the sinus wall. In order to elucidate the pathogenesis of dural AVM's of the lateral and sigmoid sinuses, histopathological profiles of this disease were studied in serial sections of completely resected lesions from three patients. The essential lesion was histologically confirmed to be a dural arteriovenous fistula within the wall of the venous sinuses. The etiology process of this disease and its progression were evaluated.

The extraction of a stainless steel wire embedded in an epoxy resin has been studied as a function of the embedded length. The models developed to elucidate the dependence of the debonding stress and the pull-out stress on the embedded length are applied successfully to the experimental results. The nonlinear variation of the debonding stress with the embedded length is caused by the distribution of shear stress along the wire. The variation of pull-out stress with embedded length is caused by the decrease of the frictional stress due to the Poisson contraction of the wire under tensile stress. The effect of wire contraction on the friction process was confirmed by using different initial wire tensions. The residual compressive stress at the interface due to resin shrinkage and the coefficient of friction were determined from the analysis of the pull-out process.

Direct sinus packing was found to be highly effective for the treatment of dural AVFs that empty into the isolated sinus. Measurement of changes in sinus pressure and sinus blood gas levels was useful for monitoring the progress of direct sinus packing.