Vascular Casting and Scanning Electron Microscopy in Diabetes

Scanning electron microscopic (SEM) studies of the vascular casts of human eyes removed at autopsy from subjects with a long-standing history of Diabetes Type I were performed. Changes in the choroidal vasculature include: Venal focal dilations and narrowings, increased tortuosity, hypercellularity, increased formation of vascular loops and microaneurysms in choriocapillaries and formation of sinus-like structures between choroidal lobules. This study strongly supports earlier light microscopic and transmission electron microscopy observations on changes in the choroid. The retinal vascular changes shown by SEM are microaneurysm formation, drop-out of capillaries and neovascularization. Changes in the choroid, especially in diabetic choriocapillaries can be suspected to be a supporting factor in diabetic retinopathy by a decrease of oxygenation of the outer layers of the retina

Scanning Electron Microscopy of Microcorrosion Casts: Applications in Ophthalmologic Research

In light of the complicated nature of the ocular vasculature, it has been difficult to define the normal ocular anatomy by reference to two-dimensional tissue sections. Since it provides three-dimensional replicas, scanning electron microscopy (SEM) of vascular corrosion casts has therefore been an invaluable addition to the study of ocular vasculature. This technique also often permits identification of a normal vessel\u27s arterial, venous, or capillary nature by its surface features. In addition, this technique is finding increased use in defining anatomical features of human vascular disease and is especially well suited for the study of experimental neovascularization as it relates to the eye. This paper reviews the application of SEM of microscopic casts to the study of normal and diseased ocular vessels, as well as the contribution of this method to studies of experimental ocular neovascularization

Effect of tissue fit on corneal shape after transplantation

Postkeratoplasty astigmatism is now a major problem preventing visual recovery. Certain postopertive topographic characteristics are felt to be dictated by the fit of the donor corneal button in its recipient bed. Deficient tissue at the wound is predicted to contribute to the location of the steep meridian and excess tissue to the location of the flat meridian. In an eight-cat sample using our Fit Assessment Method and Photogrammetric Index Method, the authors tested the relationship between button fit in recipient bed and resulting corneal curvature at approximately 42, 161, and 289 postoperative days. Corneal symmetry improved between the first and second postoperative periods. Deficient tissue led to steepened curvature and ample tissue to flattened curvature in the first measurement period. When buttons fit poorly, deficient tissue led to steepness in the first postoperative period, but led to flattened curvature 90 deg away from the deficient tissue meridian in the second and third periods. The relationship between ample tissue and flattest postoperative curvature did not depend on the magnitude of button-bed disparity in any period. Corneal elasticity appeared to influence the way tissue disparity affected postoperative topography. Our findings support Troutman's balloon mode. When there was a large amount of uncompensated tissue disparity, the tissue deficiency exerted a force that shortened the translimbal chord. This produced both steepened curvature parallel to this chord soon after surgery and flattened curvature at 90 deg to the chord in the stable postoperative cornea

A new photogrammetric method for quantifying corneal topography

Attempts to describe normal corneal shape and to represent corneal topography by an array of discrete points have limited usefulness. A quantitative photogrammetric method that produces indices to describe corneal shape was developed. Four indices depict the departure of keratographic rings from circularity, and two indices express the trends and consistencies of all the rings from one keratograph. This photogrammetric index method (PIM) was evaluated against established measurement techniques. Values for the six indices were computed for groups (10 corneas each) of symmetrical, regularly astigmatic, and keratoconic corneas that had been defined by keratometry and clinical criteria. Predictions of the differences among groups were formulated for each index based on group descriptions and anticipated manual tracing and/or digitization error. Parametric and nonparametric tests of significance supported most predictions. The asymmetry of irregularly astigmatic keratoconic corneas, the variability of their orthogonal principal meridians, and an increasing symmetry toward their peripheries were documented clearly. The circularity of symmetrical group rings and the ellipticity of regularly astigmatic group rings were also evident. Preliminary norms are offered to illustrate the usefulness of the PIM in defining groups of corneas with the same histories and in classifying individual corneas

Effect of polythiophene content on thermomechanical properties of electroconductive composites

The thermal, mechanical and electrical properties of polymeric composites combined using polythiophene (PT) dopped by FeCl3 and polyamide 6 (PA), in the aspect of conductive constructive elements for organic solar cells, depend on the molecular structure and morphology of materials as well as the method of preparing the species. This study was focused on disclosing the impact of the polythiophene content on properties of electrospun fibers. The elements for investigation were prepared using electrospinning applying two substrates. The study revealed the impact of the substrate on the conductive properties of composites. In this study composites exhibited good thermal stability, with T5 values in the range of 230–268 °C that increased with increasing PT content. The prepared composites exhibited comparable PA Tg values, which indicates their suitability for processing. Instrumental analysis of polymers and composites was carried out using Fourier Transform Infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM)

Przydatność badań ultrasonograficznych w rozpoznawaniu i w ocenie odległych wyników leczenia operacyjnego zwężenia podmiedniczkowego moczowodu u noworodków

Background: Pyeloureteral stricture in neonates requires early diagnosis and treatment for the reason that leads to infections, formation of concrements and destruction of renal parenchyma. Aim: Evaluation of usefulness of ultrasound examinations in diagnosis of neonatal pyeloureteral stricture and their value in postoperative follow-up. Material/Methods: The study comprised of 54 newborns (33 boys and 29 girls) with pyloureteral stricture diagnosed by ultrasound, including 52 (96%) of unilateral (27 left and 25 right sided) and 2 cases of bilateral stricture. In 15 (28%) neonates high-grade pelvic dilatation was found. Results: Operative treatment with use of Anderson-Hynes method was applied in 6(11%) of children in first month of life, in 21 (39%) of children between 2 and 6 month of life and in 27(50%) in second half of first year of life. Long-term follow-up was performed in 46 children of mean age 7,8 years using abdominal ultrasound. The very good result of surgical intervention was noted in 50% of children, good effect in 43,5% and poor outcome in 3 children: 1 with large pelvic dilatation and two cases with lack of renal function confirmed by scintigraphy. Conclusions: Abdominal ultrasound in neonates allow not only to make early diagnosis of pyeloureteral stricture but also provide quick and proper qualification to operative treatment. Abdominal ultrasound, among other ways of imaging, as a safe and useful, should be method of choice in follow-up after operative treatment of pyeloureteral stricture in children. Follow-up using abdominal ultrasound in children after Anderson-Hynes operation confirm beneficial effects of such treatment on reconstruction of dynamics of upper urinary tract, prevention of deformation of pyelocaliceal system and damage of renal parenchyma

Prognostic value of radical cystoprostatectomy in men with bladder cancer infiltrating prostate versus co-existing prostate cancer: a research study

<p>Abstract</p> <p>Background</p> <p>The aim of the following study is to evaluate the advancement of incidentally diagnosed prostate cancer in specimen after cystoprostatectomies caused by muscle-invasive bladder cancer. Secondly we assessed the survival in patients after radical cystoprostatectomy whose postoperative specimen was characterized by the presence of co-existing prostate cancer or prostate infiltration by urothelial bladder cancer.</p> <p>Methods</p> <p>Between 1993 and 2009 a total of 320 patients with muscle-invasive bladder cancer underwent cystoprostatectomy. The first analyzed group consisted of 52 patients with bladder cancer infiltrating prostate, while the second group consisted of 21 patients with co-existing prostate cancer. In all patients cancer specific survival and progression were analyzed. Average follow up was 75.2 months (range: 0 - 181).</p> <p>Results</p> <p>Cancer-specific survival was significantly shorter in group I (p = 0.03). Neoplastic progression in patients from group I was observed in 42.2% of patients, while in patients from group II in 23.6% of patients (p = 0.04). No statistical difference was observed in the percentage of positive lymph nodes between the groups (p = 0.22). The median Gleason score in patients with co-existing prostate cancer was equal to 5. The stage of prostate cancer pT₂/pT₃was equal to 20 (96%)/1 (4%) patients. 12 (57%) prostate cancers were clinically insignificant. Biochemical recurrence occurred in 2 (9%) patients.</p> <p>Conclusions</p> <p indent="1">1. Incidentally diagnosed prostate cancer in specimen after cystoprostatectomies is frequently clinically insignificant and characterized by low progression.</p> <p indent="1">2. Patients with bladder cancer infiltrating prostate are characterized by higher percentage of progression and death in comparison with patients with co-existing prostate cancer.</p

Polyaniline coated conducting fabrics : chemical and electrochemical characterization

Polyaniline coated conducting fabrics have been obtained by chemical oxidation of aniline by potassium peroxydisulfate on polyester fabrics. Two different acids have been employed to carry out the synthesis (HCl and H2SO4), obtaining the best results of conductivity with the latter one. The conducting fabrics have been characterized chemically by means of Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR), energy dispersive X-Ray (EDX) and X-ray photoelectron spectroscopy (XPS). The morphology of the coatings has been observed by means of scanning electron microscopy (SEM). The conducting properties of the fabrics have been measured by means of electrochemical impedance spectroscopy (EIS). The electrochemical characterization has been carried out by means of cyclic voltammetry (CV) and scanning electrochemical microscopy (SECM). The conducting fabrics have also shown electrochromic properties, changing its color from green yellowish at −1 V to dark green at +2 V. The durability of the coating has been evaluated by means of washing and rubbing fastness tests.Authors thank to the Spanish Ministerio de Ciencia e Innovacion and European Union Funds (FEDER) (contract CTM2010-18842-C02-02) and Universitat Politecnica de Valencia (Primeros Proyectos de Investigacion (PAID-06-10)) for the financial support. J. Molina is grateful to the Conselleria d'Educacio (Generalitat Valenciana) for the FPI fellowship

Electrical Conductivity of Electrospun Polyaniline and Polyaniline-Blend Fibers and Mats

Submicrometer fibers of polyaniline (PAni) doped with (+)-camphor-10-sulfonic acid (HCSA) and blended with poly(methyl methacrylate) (PMMA) or poly(ethylene oxide) were electrospun over a range of compositions. Continuous, pure PAni fibers doped with HCSA were also produced by coaxial electrospinning and subsequent removal of the PMMA shell polymer. The electrical conductivities of both the fibers and the mats were characterized. The electrical conductivities of the fibers were found to increase exponentially with the weight percent of doped PAni in the fibers, with values as high as 50 ± 30 S/cm for as-electrospun fibers of 100% doped PAni and as high as 130 ± 40 S/cm upon further solid state drawing. These high electrical conductivities are attributed to the enhanced molecular orientation arising from extensional deformation in the electrospinning process and afterward during solid state drawing. A model is proposed that permits the calculation of mat conductivity as a function of fiber conductivity, mat porosity, and fiber orientation distribution; the results agree quantitatively with the independently measured mat conductivities.United States. Army Research Office (Institute for Soldier Nanotechnologies, Contract ARO W911NF-07-D- 0004