Increased expression of paxillin is found in human oesophageal squamous cell carcinoma: a tissue microarray study.

Oesophageal cancer is one of the most common cancers worldwide. Currently, the tumour, node, metastasis (TNM) staging system is the primary method for determining its extent and prognosis, however, data suggest this system does not predict prognosis accurately. Research has, therefore, concentrated on searching for specific biomarkers. Paxillin has been shown to play an important role in controlling cell spread and migration. Its over-expression is considered to correlate with the prognosis of some types of cancers, however, the relationship between paxillin expression and clinical outcome in oesophageal cancer has not been investigated. This study determined the expression of paxillin by immunohistochemistry on the tissue microarray of 100 oesophageal squamous cell cancer patients followed up for a mean of 55 months. Paxillin was over-expressed in tumours in 27/100 cases, compared with 6/100 cases for adjacent non-tumoural cells. No correlation occurred between expression of paxillin and overall patient survival, hence paxillin is not an effective prognostic marker in these patients.

Computer simulations of electrorheological fluids in the dipole-induced dipole model.

We have employed the multiple image method to compute the interparticle force for a polydisperse electrorheological (ER) fluid in which the suspended particles can have various sizes and different permittivities. The point-dipole (PD) approximation, being routinely adopted in the computer simulation of ER fluids, is known to err considerably when the particles approach and finally touch due to multipolar interactions. The PD approximation becomes even worse when the dielectric contrast between the particles and the host medium is large. From the results, we show that the dipole-induced-dipole (DID) model yields very good agreements with the multiple image results for a wide range of dielectric contrasts and polydispersity. As an illustration, we have employed the DID model to simulate the athermal aggregation of particles in ER fluids, both in uniaxial and rotating fields. We find that the aggregation time is significantly reduced. The DID model partially accounts for the multipolar interaction and is simple to use in the computer simulation of ER fluids.

Relaxation of surface charge on rotating dielectric spheres: Implications on dynamic electrorheological effects.

We have examined the effect of an oscillatory rotation of a polarized dielectric particle. The rotational motion leads to a redistribution of the polarization charge on the surface of the particle. We show that the time-averaged steady-state dipole moment is along the field direction, but its magnitude is reduced by a factor that depends on the angular velocity of rotation. As a result, the rotational motion of the particle reduces the electrorheological effect. We further assume that the relaxation of the polarized charge is arised from a finite conductivity of the particle or host medium. We calculate the relaxation time based on the Maxwell-Wagner theory, suitably generalized to include the rotational motion. Analytic expressions for the reduction factor and the relaxation time are given and their dependence on the angular velocity of rotation will be discussed.

Nonlinear ac response of anisotropic composites.

When a suspension consisting of dielectric particles having nonlinear characteristics is subjected to a sinusoidal (ac) field, the electrical response will in general consist of ac fields at frequencies of the higher-order harmonics. These ac responses will also be anisotropic. In this work, a self-consistent formalism has been employed to compute the induced dipole moment for suspensions in which the suspended particles have nonlinear characteristics, in an attempt to investigate the anisotropy in the ac response. The results showed that the harmonics of the induced dipole moment and the local electric field are both increased as the anisotropy increases for the longitudinal field case, while the harmonics are decreased as the anisotropy increases for the transverse field case. These results are qualitatively understood with the spectral representation. Thus, by measuring the ac responses both parallel and perpendicular to the uniaxial anisotropic axis of the field-induced structures, it is possible to perform real-time monitoring of the field-induced aggregation process.

First-principle approach to dielectric behavior of nonspherical cell suspensions.

We present a theoretical study of the dielectric behavior of cell suspensions by employing the Bergman-Milton spectral representation of the effective dielectric constant. By means of the spectral representation, we derive the dielectric dispersion spectrum in terms of the electrical and structure parameters of the cell models. Our results show that a better agreement with the experimental data can be obtained, provided that we introduce a conductivity contrast t=sigma(2)/(sigma(2)-sigma(1)). We find that the conductivity of the cell cytoplasm sigma(1) can be much larger than that of the suspending medium sigma(2), in contrast to the previous claim that sigma(1) approximately sigma(2).

Nonlinear ac response of an electrorheological fluid.

The applied electric field used in most electrorheological (ER) experiments is usually quite high, and nonlinear ER effects have been measured recently. When a nonlinear ER fluid is subjected to a sinusoidal (ac) field, the electrical response will in general consist of ac fields at frequencies of the higher-order harmonics. In this paper, a self-consistent formalism has been employed to compute the induced dipole moment for ER fluids in which the suspended particles have nonlinear characteristics, in an attempt to investigate the ac response of a nonlinear ER fluid.

Expression of epidermal growth factor in salivary adenoid cystic carcinoma.

This study used an immunohistochemical technique to assess the expression of epidermal growth factor (EGF) in 40 specimens of salivary adenoid cystic carcinoma (ACC), 7 specimens of labial glands adjacent to mucocele, and 5 specimens of normal submandibular glands. In normal submandibular glands, immunohistochemically detectable EGF was demonstrated in all ductal segments, including intercalated, striated, and excretory duct cells. No EGF positive staining was found in acinar compartments. including serous and mucous acinar cells. In degenerated labial glands adjacent to mucocele, no EGF staining was detected in the remaining acinar and ductal cells. In salivary ACCs, positive EGF immunostaining was observed in one of the 5 (20%) ACCs with a solid pattern and in 13 of the 35 (37.1%) ACCs with a tubular-cribriform pattern. The overall EGF expression rate in 40 salivary ACCs was 35%. Positive EGF staining was predominantly found in tubular structures in the tubular ACCs and in duct-like structures in large cribriform patterns or in the stroma of the cribriform ACCs. There was no significant correlation between EGF expression in salivary ACCs and any of the clinicopathological parameters including patient age and sex, cancer location, TNM status, clinical stage, histologic type, perivascular or perineural invasion, focal necrosis of tumor, and cellular atypia. We conclude that the duct segments of the normal submandibular gland are the sites of EGF synthesis and secretion. In degenerated labial glands adjacent to mucocele, EGF synthesis is completely inhibited. Furthermore, EGF is mainly biosynthesized in cells forming tubular or duct-like structures in tubular or cribriform salivary ACCs, and EGF may play a biologic role, particularly as a mitogen in salivary ACC growth.