Cartilage-sparing otoplasty: a review with long-term results

Prominent ears are the most frequent congenital deformity in the head and neck region. Anatomy of normal and prominent ears as well as the psychological aspects of prominent ears are reviewed. Two types of surgical technique are described with emphasis on the cartilage-sparing technique. A sound pre-operative analysis, focusing on all parts of the deformity, and surgical techniques which are gradually applied to these deformities should result in pleasing, permanent changes for the vast majority of patients. In our opinion, a combination of cartilage-sparing techniques augmented with cartilage-weakening procedures give predictable long-term results with a natural appearing ear and concomitant few, easily treated complications.     

The effect of inducer polarity and contrast on the perception of illusory figures

A study designed to determine how inducer-surround contrast and inducer polarity affect the contour clarity and the lightness of illusory figures is reported. Using magnitude estimation procedures, ten naive subjects rated both the contour clarity and the lightness of Kanizsa squares. The magnitude of the inducer-surround contrast and the inducer polarity (all-black, all-white, or black-and-white) were varied randomly on each trial. The data indicate that contour clarity increases with contrast at the same rate across polarity conditions but that contour clarity at any given contrast level depends significantly on polarity. Contour clarity judgments were significantly lower when the inducers were all-white than when the inducers were all-black or black-and-white, and significantly greater in the 'mixed' polarity case (black-and-white inducers) than in the 'same' polarity case (the average of the all-black and all-white inducer conditions). Inducer contrast and polarity significantly affected the lightness of the illusory figure in a manner consistent with simultaneous spatial contrast. Also, for a given increment in contrast, contour clarity altered significantly more than surface lightness, regardless of inducer polarity. The findings suggest that the mechanism which mediates boundary formation is sensitive to the direction of contrast, and that the boundary formation mechanism is more sensitive than the surface lightness mechanism to changes in contrast magnitude. The results are considered within the context of neural network models of form perception.     

Shape‐memory behavior of thermally stimulated polyurethane for medical applications

Shape memory polymers (SMPs) have been of great interest because of their ability to be thermally actuated to recover a predetermined shape. Medical applications in clot extracting devices and stents are especially promising. We investigated the thermomechanical properties of a series of Mitsubishi SMPs for potential application as medical devices. Glass transition temperatures and moduli were measured by differential scanning calorimetry and dynamic mechanical analysis. Tensile tests were performed with 20 and 100% maximum strains, at 37 and 80°C, which are respectively, body temperature and actuation temperature. Glass transitions are in a favorable range for use in the body (35–75°C), with high glassy and rubbery shear moduli in the range of 800 and 2 MPa respectively. Constrained stress–strain recovery cycles showed very low hysteresis after three cycles, which is important to know for preconditioning of the material to ensure identical properties during applications. Isothermal free recovery tests showed shape recoveries above 94% for MP5510 thermoset SMP cured at different temperatures. One material exhibited a shape fixity of 99% and a shape recovery of 85% at 80°C over one thermomechanical cycle. These polyurethanes appear particularly well suited for medical applications in deployment devices such as stents or clot extractors. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3882–3892, 2007     

Paraoxonase (PON1) gene in mice: sequencing, chromosomal localization and developmental expression

PURPOSE: To retrospectively examine the optic disc photographs of a glaucoma population for optic disc haemorrhages, vascular occlusions and vascular abnormalities. METHODS: The optic disc photographs of 906 eyes of glaucoma and suspect glaucoma patients were examined. Optic disc photographs were taken annually, where possible, with the follow-up period varying between 1 and 14 years duration (mean, 2.89). Glaucoma patients are regularly reviewed every 4-6 months and glaucoma suspects every 1-2 years, depending on the ophthalmologist. Low-tension glaucoma patients were reviewed more frequently (mean, every 2.6 months). The results of the findings were compared to a control group of 39 subjects with a mean follow-up period of 7 years, using Fisher's exact test. RESULTS: It was found that during the period under review, 7.4% (n = 67) of eyes had optic disc haemorrhages. The highest frequency of optic disc haemorrhages (37.5%) was found in the low tension glaucoma group (P = 0.0001) followed by 11% of primary open-angle glaucoma eyes (P = 0.03). In the normal group there were three eyes with optic disc haemorrhages and one with a disc collateral, which constitutes 5.1% vascular changes in this sub-group. Of the study eyes 2.8% had central retinal vein occlusions, 1.3% branch vein occlusion, 1.2% disc vessel abnormalities (loops) and 1.1% disc collaterals. Discrete nerve fibre layer haemorrhages and microaneurysms were found in 0.8% and 1.8% of eyes, respectively. CONCLUSIONS: A total of 16.8% of the eyes observed in this study had either disc haemorrhages or vascular changes. The underlying trend of vascular and haemorrhagic changes in glaucoma are demonstrated in this sample, which is in general agreement with previous studies. The high percentage of optic disc haemorrhages in low tension glaucoma is highlighted. The presence of microaneurysms and nerve fibre layer haemorrhages is interesting but of unknown significance.     

Cardiovascular collapse after femoral prosthesis surgery for acute hip fracture

Traumatic rupture of Dupuytren's contracture is rare. It has been reported only twice in recent times and only on four previous occasions over the last millenium. These cases are reported and the forces involved in rupturing Dupuytren's contracture are discussed.     

Error correction techniques for high-performance differential A/Dconverters

Error correction techniques that overcome several error mechanism that can affect the accuracy of charge-redistribution analog-to-digital converters (ADCs) are described. A correction circuit and a self-calibration algorithm are used to improve the common-mode rejection of the differential ADC. A modified technique is used to self-calibrate the capacitor ratio errors and obtain higher linearity. The residual error of the ADC due to capacitor voltage dependence is minimized using a quadratic voltage coefficient (QVC) self-calibration scheme. A dual-comparator topology with digital error correction circuitry is used to avoid errors due to comparator threshold hysteresis. A fully differential charge-redistribution ADC implemented with these techniques was fabricated in a 5-V 1-μm CMOS process using metal-to-polysilicide capacitors. The successive-approximation converter achieves 16-b accuracy with more than 90 dB of common-mode rejection while converting at a 200-kHz rate     

Cytolytic activity of peripheral blood blast cells from patients with acute myeloid leukemia

The results of the present study demonstrate that cells with the morphologic and phenotypic characteristics of blast cells that are obtained from the peripheral blood of patients with newly-diagnosed or recurrent acute myeloid leukemia (AML) can be stimulated by gamma interferon + lipopolysaccharide (IFN/LPS) to mediate in vitro cytolysis of an NK-insensitive hepatoma cell line. The conditions of IFN/LPS induction and subsequent assessment of cytotoxicity that were employed were identical to those used conventionally to test macrophage-mediated tumor cell cytotoxicity. What was totally unexpected was that these same blast cells, in the absence of stimulation with IFN/LPS, were also found to mediate high levels of spontaneous cytotoxicity against autologous bone marrow cells and against the U937 human promonocytic leukemia cell line in vitro. This high level of spontaneous cytotoxicity against autologous bone marrow or U937 promonocytic leukemia cells was not enhanced by IFN/LPS or MCSF under conditions that stimulated cytotoxic function in normal blood monocytes and was markedly reduced by pretreatment of the blast cells with IL2 under conditions that induced potent NK/LAK-mediated cytotoxicity. Neutralizing antibodies against TNFalpha and/or IL1alpha/beta eliminated the cytolytic function of blast cells against autologous bone marrow or U937 promonocytic leukemia targets. These findings demonstrate the existence of a population of cells with the morphologic characteristics of blast cells in the peripheral blood of AML patients which has the capacity to mediate spontaneous cytolysis of autologous bone marrow cells or a promonocytic leukemia cell line. These cells may be an immature variant of normal precursors produced as a consequence of the disordered hematopoietic environment in the marrow of AML patients. Alternatively, this function may be mediated by a subset of the leukemic blasts themselves.