Normal variations of the temporal bone on high-resolution CT: their incidence and clinical significance

We evaluated normal variations of the temporal bone on high-resolution computed tomograms (HR-CTs) and investigated their incidence. HR-CTs of the temporal bones of 325 patients were retrospectively reviewed. Six groups of variants, which were considered important for presurgical planning, were evaluated on HR-CTs. These included: (1) an incomplete bony covering of a high-positioned jugular bulb; (2) severe asymmetry of the jugular foramen; (3) an anteriorly located sigmoid sinus; (4) a deep sinus tympani; (5) a large internal auditory canal; and (6) a large cochlear aqueduct. The frequency of the variations were as follows: (1) 2.4%; (2) 4.0%; (3) 1.6%; (4) 5.9%; (5) 2.3%; and (6) 3.0%. Bilateral involvement with variation (4), (5) and (6) was frequently seen. Normal anatomical variations of the temporal bone are therefore not rare and awareness of the possible variants is necessary before surgery of the inner ear, middle ear and posterior fossa.     

ANALYSIS OF AXISYMMETRIC FORGING OF POROUS MATERIALS BY THE FINITE ELEMENT METHOD

Axisymmetric forging of powdered-metal preforms was analyzed by the finite element method neglecting the effect of temperature on deformation. A remeshing program based on the area-weighted-average technique was developed and tested by simulating forging of the flange-hub shape. Then the analysis was performed for forging of a pulley blank. The detailed deformation characteristics for the different preform shapes under the two frictional conditions were obtained. A comparison between the prediction and the experiment regarding proper preform design to forge defect-free pulley blank demonstrates that the finite element analysis is useful for further developments in preform design in powdered-metal forging.     

Hybrid integration of a laser diode and high-silica multimode optical channel waveguide on silicon

An InGaAsP laser diode with 1.34 ?m wavelength and a high-silica multimode optical waveguide were integrated on a common Si substrate using an alignment guide, which is formed simultaneously with the waveguide, for laser diode mounting. The laser-waveguide coupling efficiency was 30%.     

Impact of androgen deprivation prior to radical prostatectomy for T1, T2 prostate cancer on the likelihood of curative surgery

BACKGROUND: Extracapsular extension is commonly seen in patients undergoing radical prostatectomy for localized prostate cancer due to understaging of disease. One possible approach to reduce the likelihood of extracapsular disease is androgen deprivation prior to radical prostatectomy, neoadjuvant therapy. However, adequate application is not clear. We analyzed the outcome of neoadjuvant therapy and radical prostatectomy in an attempt to expand our understanding on indications of neoadjuvant therapy. METHODS: Forty-six selected patients with clinical T1 or T2 prostate cancer were retrospectively reviewed. Twenty-two patients underwent neoadjuvant therapy (group N) that mainly consists of LH-RH agonist. The duration of neoadjuvant therapy, varied from 1 to 12 months with the mean being 4 months. Twenty-four underwent radical prostatectomy alone (group S). RESULTS: In the group N and group S, 59% and 33% had either organ confined disease (OCD) or specimen confined disease (SCD) respectively. When the patients had OCD or SCD, they were defined as surgically cured patients. In the patients with clinical stage T1b, T1c, and T2 disease, likelihood of surgical cure were 100%, 50%, 46.7% in group N, 100%, 20%, 11%, in group S respectively. In the patients with initial serum PSA less than 10 ng/ml and more than 10.1 ng/ml, likelihood of surgical cure were 83.3% and 50% in group N, 63.6% and 15.4% in group S, respectively. Likelihood of surgical cure was higher in the patients with well differentiated carcinoma both in group N and group S. All the patients with serum PSA less than 0.1 ng/ml after neoadjuvant therapy had OCD. CONCLUSION: Neoadjuvent therapy could be beneficial either in the patients with moderately or in the poorly differentiated adenocarcinoma of prostate especially in the group with initial serum PSA more than 10.1 ng/ml. However, in patients both with well differentiated adenocarcinoma and the initial serum PSA less than 10 ng/ml, no evidence of beneficial effect on the likelihood of OCD or SCD was observed. PSA after neoadjuvant therapy could be useful predictor for the pathological outcome.     

A regularized boundary integral equation method for elastodynamic crack problems

This paper presents a double layer potential approach of elastodynamic BIE crack analysis. Our method regularizes the conventional strongly singular expressions for the traction of double layer potential into forms including integrable kernels and 0th, 1st and 2nd order derivatives of the double layer density. The manipulation is systematized by the use of the stress function representation of the differentiated double layer kernel functions. This regularization, together with the use of B-spline functions, is shown to provide accurate numerical methods of crack analysis in 3D time harmonic elastodynamics.     

Telomerase activity in human acute myelogenous leukemia: inhibition of telomerase activity by differentiation-inducing agents

The terminal regions of human chromosomes, the telomeres, shorten with each cell division in most normal somatic cells. Telomerase, a ribonucleoprotein that synthesizes telomeric DNA onto chromosomal ends, is activated in germline cells and almost all tumor cells. Telomerase activity maintains the stability of telomere length, resulting in indefinite cellular proliferation (immortality). In the present study, telomerase activity was analyzed in leukemic mononuclear blood cells obtained from 56 patients with acute myelogenous leukemia (AML) with known cytogenetic alterations. Heterogenous levels of telomerase activity were observed and generally correlated with cytogenetic status. Patients with 11q abnormalities and -5/-7 (unfavorable cytogenetics) tended to have high telomerase activity compared with cells obtained from AML patients with other types of cytogenetics. Additional studies with a larger cohort of patients will determine whether these differences are statistically significant. Chemotherapy agents that result in differentiation of leukemic cells also resulted in inhibition of telomerase activity. Knowledge of telomerase activity in patients with AML, before and throughout therapy, may have clinical utility for following disease progression and may predict early cancer relapse.     

Physicochemical properties of high-molecular-weight poly(α,β-malic acid) synthesized by direct polycondensation

Summary We studied high-molecular-weight α,β-PMA synthesized by polycondensation in order to find possible applications for biomaterials. Its solubility in different solvents, its hydrolysis and its acidity were also examined. The α,β-PMA molecular weight increased markedly up to 20 h and then decreased showing that the molecular weights for synthesized α,β-PMA depends on the reaction time. We prepared high-yield α,β-PMA with a molecular weight of 3600 by direct polycondensation using tin(II) chloride as a catalyst at 130°C for 20 hours and concluded that our method is suitable to synthesize higher molecular weight compounds of α,β-PMA. Received: 20 December 2002/Revised version: 18 February 2003/ Accepted: 22 February 2003 Correspondence to Tetsuto Kajiyama     

Intestinal mast cell response and mucosal defence against Strongyloides venezuelensis in interleukin-3-hyporesponsive mice

Mineralization in the pulp is a common finding in permanent as well as primary teeth and is associated with caries, aging, traumatic injuries and systemic conditions. This article describes an unusual pattern of pulpal calcification. A tube-like calcified structure formed in the dental pulp of primary incisors following mild traumatic injuries. It was studied by clinical, radiographic and histologic evaluation and by scanning electron microscopy. The tube-like structure was found to extend along the entire length of the pulp canal. Generally it was separated from the root dentin by normal pulp tissue, but was connected to the dentin in some sites. It had the histologic appearance of osteodentin with cell inclusions in a ring-like formation that was incomplete in places. The scanning electron microscope study showed rough inner and outer surfaces of a tube-like structure with openings that seemed to be dentinal tubules.     

Diffraction by a terminated semi-infinite parallel-plate waveguidewith three-layer material loading

The plane wave diffraction by a terminated semi-infinite parallel-plate waveguide with three-layer material loading is rigorously analyzed for E polarization using the Wiener-Hopf technique. Introducing the Fourier transform for the scattered field and applying boundary conditions in the transform domain, the problem is formulated in terms of the simultaneous Wiener-Hopf equations, which are solved via the factorization and decomposition procedure. The scattered field is evaluated by taking the inverse Fourier transform and applying the saddle point method. Representative numerical examples of the radar cross section (RCS) are given for various physical parameters and the backscattering characteristics are discussed in detail. Some comparisons with a high-frequency technique are also given to validate the present method