A case of foramen magnum meningioma in which case enhanced three-dimensional CT scan was valuable for preoperative evaluation of the surgical approach

We report a case of foramen magnum meningioma in which case enhanced three-dimensional CT scan was valuable for preoperative evaluation of the surgical approach. A 53-year-old woman had suffered from stiffness and pain in the left occipital region and numbness of the left side of the face for about 2 years before admission. She had also weakness and numbness of the left side of her body for about 2 months before admission, and dysphagia and pain in the occipital region and in the posterior region of the neck produced by straining for about 1 month before admission. Neurological examination revealed left hemiparesis, and hypalgesia and tactile hypesthesia of the left side of the body, including the face. Plain X-P was normal. Enhanced CT scan and gadolinium enhanced MRI revealed a well-enhanced mass attached to the left anterolateral part of the foramen magnum. The left occipital condyle was observed at the lateral side of the attachment part of this mass. Angiography revealed tumor feeders from the meningeal branches of the left vertebral artery and the left ascending pharyngeal artery. Enhanced three-dimensional CT scan clearly showed that the tumor was attached to the left anterolateral part of the foramen magnum, that the left occipital condyle was at the lateral side of the attachment part of this mass and that the jugular foramen and jugular tubercle were situated superolateral to the attachment part of this mass. Considering these factors, we decided that removal of the posterior part of the left occipital condyle was necessary, but removal of the left jugular tubercle was not necessary for a good operative view from the left posterior lateral direction. The tumor was totally removed successfully and good results were obtained by the transcondylar approach without removal of the jugular tubercle. Histology of the tumor revealed meningothelial meningioma. In this case, preoperative evaluation with enhanced three-dimensional CT scan was helpful for deciding the surgical approach. With enhanced three-dimensional CT scan, it is easy to judge whether removal of the posterior part of the occipital condyle and/or the jugular tubercle is necessary for a good operative view, and we can get good images revealing the relationships between the tumor and surrounding structures. Preoperative evaluation with enhanced three-dimensional CT scan is very useful especially in this kind of situation.     

Enhancement of human parainfluenza virus-induced cell fusion by pradimicin, a low molecular weight mannose-binding antibiotic

Oligosaccharides, especially mannose residues, expressed on the cell surface, are thought to be important for virus-induced membrane fusion. We examined the effect of mannose-binding compounds, pradimicin derivative BMY-28,864 (PRM) and concanavalin A (Con A), on cell fusion of human parainfluenza type 2 virus (hPIV2)-infected HeLa cells. Syncytium formation of hPIV2-infected HeLa cells was suppressed in the presence of Con A. On the other hand, PRM enhanced cell fusion of hPIV2-infected HeLa cells. These effects were blocked by addition of mannose-rich mannan. However, PRM shows little effect on virus growth and the expression of viral glycoproteins on the cell surface in hPIV2-infected HeLa cells. Fluorescein-isothiocyanate-labeled pradimicin and Con A bound to both uninfected and hPIV2-infected mononuclear cells, indicating that these compounds have an affinity to several cellular component(s). In contrast to Con A, PRM had little affinity to the viral glycoproteins. It is inferred from these results that the enhancement of hPIV2-induced cell fusion is probably due to the interaction between PRM and cellular component(s).     

Nonlinear dynamics of offshore structures under sea wave and earthquake forces

A study of dynamic response of offshore structures in random seas to inputs of earthquake ground motions is presented. Emphasis is placed on the evaluation of nonlinear hydrodynamic damping effects due to sea waves for the earthquake response. The structure is discretized using the finite element method. Sea waves are represented by Bretschneider’s power spectrum and the Morison equation defines the wave forcing function. Tajimi-Kanai’s power spectrum is used for the horizontal ground acceleration due to earthquakes. The governing equations of motion are obtained by the substructure method. Response analysis is carried out using the frequency-domain random-vibration approach. It is found that the hydrodynamic damping forces are higher in random seas than in still water and sea waves generally reduce the seismic response of offshore structures. Studies on the first passage probabilities of response indicate that small sea waves enhance the reliability of offshore structures against earthquakes forces.     

Characteristics of sol-gel derived PZT thin films with lead oxide cover layers and lead titanate interlayers

The sol-gel derived PbZr_0.53Ti_0.47O₃ (PZT) films were fabricated on the bare Pt/Ti/SiO₂/Si substrates or the same substrates coated by the PbTiO₃ (PT) interlayers. The post-deposition annealing temperature and time were optimized when the PbO cover layers and PbO vapour-containing atmosphere were compared with each other and adopted as the method to diminish the lead-loss problem during the high-temperature post-deposition annealing. The X-ray diffraction patterns, microstructures, and electrical properties such as relative permittivity, _r, remanent polarization, P _r, and coercive electrical field, E _c, were investigated in relation to the annealing conditions. The PZT films deposited on the bare Pt/Ti/SiO₂/Si substrates under the PbO vapour-containing atmosphere showed better electrical properties. This indicates that the PbO vapour-containing atmosphere may be the better method of lead-loss-prevention to process the lead-containing films rather than the PbO cover layer method. The electrical characteristics of the PZT films, _r=1150, a dissipation factor of 0.039, P _r=26 C cm^–2, and E _c=40.5 kV cm^–1 were measured at 1 kHz. When PZT films were deposited on substrates coated by the PT layers, PZT-PT films with single perovskite phase were derived by post-deposition annealing at 500 °C for 1 h. However, the relative electrical properties are very poor, i.e. E _r=160, P _r=2.0 C cm^–2 and E _c=75 kVcm^–1. The optimum combination for preparing PZT-PT films is a 40 nm PbTiO₃ interlayer and annealing conditions of 6 h at 550 °C in a PbO vapour-containing atmosphere; the derived films exhibit electrical properties of E _r=885, P _r=21.5 C cm^–2 and E _c=64 kV cm^–1. The combination of inserting a PT interlayer and annealing in a PbO vapour-containing atmosphere can prevent the formation of electrical short paths. In this case, nearly pin-hole-free PZT films can be grown on the PT (interlayer) /Pt/Ti/SiO₂/Si substrates. It is believed that it is possible to prepare the PZT films with nano-scale uniformity, reproducible quality, which may be worth considering for commercial applications.     

Parametric uncertainties for dynamic response evaluation of offshore structures

The dynamic characteristics involved in the loading process in the ocean environment are extremely complicated and difficult for exact evaluation. In this paper, parametric studies are presented to assess the influence of uncertainties associated with various assumptions and approximations, involved in modelling the dynamic loading processes of ocean environment, for the evaluation of dynamic response of offshore structures. These uncertainties are represented by the inertia coefficient and the drag coefficient of the Morison equation which defines the wave forcing function, the mean height of the input sea waves and the shear wave velocity of the soil. The results show that the effects of uncertainties are closely related to the natural frequency of the structure and the predominant frequency of the wave force. These uncertainties, except the variation in the shear wave velocity in the soil, contribute significantly to the dynamic response and the first passage probability evaluation of the offshore structure systems.     

Magnetic order and evolution of the electronic state aroundx=0.12 in La2?xBaxCuO4 and La2?xSrxCuO4

Muon spin rotation ( ⁺SR) measurement provides clear evidence of the antiferromagnetic order of Cu moments below 35 K for La_2–x Ba _x CuO₄ and below 15 K for La_2–x Sr _x CuO₄ in the narrow range ofx where the high-T _c superconductivity (SC) is suppressed remarkably. The results suggest that the change of the electronic state coupled with the lattice instability is relevant to the local suppression of SC and freezing of spin fluctuations of the Cu moment.     

Multihormone-producing islet cell tumor of the pancreas associated with somatostatin-immunoreactive amyloid: immunohistochemical and immunoelectron microscopic studies

OBJECTIVE: To assess the association between high but nondiabetic blood glucose levels and the risk of death from all causes, coronary heart disease (CHD), cardiovascular disease, and neoplasms. RESEARCH DESIGN AND METHODS: We studied the 20-year mortality of non-diabetic, working men, age 44-55 years, in three European cohorts known as the Whitehall Study (n = 10,025), the Paris Prospective Study (n = 6,629), and the Helsinki Policeman Study (n = 631). These men were identified by their 2-h glucose levels following an oral glucose tolerance test and by the absence of a prior diagnosis of diabetes. As the protocol for the oral glucose tolerance test and methods for measuring glucose differed between studies, mortality was analyzed according to the percentiles of the 2-h and fasting glucose distributions, using the Cox's proportional hazards model. RESULTS: Men in the upper 20% of the 2-h glucose distributions and those in the upper 2.5% for fasting glucose had a significantly higher risk of all-cause mortality in comparison with men in the lower 80% of these distributions, with age-adjusted hazard ratios of 1.6 (95% CI 1.4-1.9) and 2.0 (1.6-2.6) for the upper 2.5%. For death from cardiovascular and CHD, men in the upper 2.5% of the 2-h and fasting glucose distributions were at higher risk, with age-adjusted hazard ratios for CHD of 1.8 (1.4-2.4) and 2.7 (1.7-4.4), respectively. CONCLUSIONS: If early intervention aimed at lowering blood glucose concentrations can be shown to reduce mortality, it may be justified to lower the levels of both 2-h and fasting glucose, which define diabetes.