Search results for "Models"
showing 10 items of 8211 documents
Assessment of the fundamental flexural guided wave in cortical bone by an ultrasonic axial-transmission array transducer
2013
Abstract The fundamental flexural guided wave (FFGW), as modeled, for example, by the A0 Lamb mode, is a clinically useful indicator of cortical bone thickness. In the work described in this article, we tested so-called multiridge-based analysis, based on the crazy climber algorithm and short-time Fourier transform, for assessment of the FFGW component recorded by a clinical array transducer featuring a limited number of elements. Methods included numerical finite-element simulations and experiments in bone phantoms and human radius specimens ( n = 41). The proposed approach enabled extraction of the FFGW component and determination of its group velocity. This group velocity was in good ag…
Irradiation Delays Tissue Growth but Enhances Osteogenic Differentiation in Vascularized Constructs.
2018
Background Regenerative medicine is still deficient in the reconstruction after cancer due to impaired vascularization after radiotherapy and due to the need to substitute larger defects after tumor excision. Aiming at introducing regenerative medicine for reconstruction after cancer, we tested an axially vascularized bone construct in an experimental setting that mimics the clinical situation after tumor resection and adjuvant radiotherapy. Methods Twenty bone constructs were axially vascularized using microsurgically created arteriovenous loops and were implanted subcutaneously in Lewis rats. After 2 weeks, the animals were randomly allocated either to receive a clinically relevant singl…
Mitotic figure counts are significantly overestimated in resection specimens of invasive breast carcinomas.
2013
Several authors have demonstrated an increased number of mitotic figures in breast cancer resection specimen when compared with biopsy material. This has been ascribed to a sampling artifact where biopsies are (i) either too small to allow formal mitotic figure counting or (ii) not necessarily taken form the proliferating tumor periphery. Herein, we propose a different explanation for this phenomenon. Biopsy and resection material of 52 invasive ductal carcinomas was studied. We counted mitotic figures in 10 representative high power fields and quantified MIB-1 immunohistochemistry by visual estimation, counting and image analysis. We found that mitotic figures were elevated by more than th…
A potential role of interferon-gamma in the pathogenesis of venous leg ulcers.
2005
Venous leg ulcer is the most severe expression of chronic venous insufficiency. Venous ulcerations are always associated with venous ambulatory hypertension, but the exact mechanism leading from pathological hemodynamics in venous circulation to the necrotic lesions in the skin still remains undiscovered. It has been shown that tissue injury in venous ulcer patients was induced by leukocytes. However, though infiltrating leukocytes have at their disposal a powerfully cytotoxic arsenal, it has not been discovered which molecular mechanisms may contribute to the skin damage. The search for this hypothetical factor responsible for the development of ulceration should be focused on mechanisms l…
Abnormal accumulation of autophagic vesicles correlates with axonal and synaptic pathology in young Alzheimer's mice hippocampus
2012
Dystrophic neurites associated with amyloid plaques precede neuronal death and manifest early in Alzheimer's disease (AD). In this work we have characterized the plaque-associated neuritic pathology in the hippocampus of young (4- to 6-month-old) PS1(M146L)/APP(751SL) mice model, as the initial degenerative process underlying functional disturbance prior to neuronal loss. Neuritic plaques accounted for almost all fibrillar deposits and an axonal origin of the dystrophies was demonstrated. The early induction of autophagy pathology was evidenced by increased protein levels of the autophagosome marker LC3 that was localized in the axonal dystrophies, and by electron microscopic identification…
A simplified method to quantitate atherosclerosis in the rabbit aorta.
2001
A simple method to quantitatively evaluate atherosclerosis in the rabbit aorta by measuring macroscopic lesion areas (%) was attempted in the present study. Ten female New Zealand white rabbits were fed on a cholesterol-rich diet (5/1000 g of food) during 4 months. Five of them were oophorectomized at the beginning and all were sacrificed at the end. Total levels of cholesterol increased from 50.7+/-14.7 mg/dl to 782.8+/-296.0. No significant differences were observed between oophorectomized and intact rabbits. At 4 months, the cholesterol-rich diet caused in both, intact and oophorectomized rabbits, atherosclerotic lesions affecting 17 and 46% of the aortic surface, respectively. This meth…
Neuronal and BBB damage induced by sera from patients with secondary progressive multiple sclerosis.
2009
An important component of the pathogenic process of multiple sclerosis (MS) is the blood-brain barrier (BBB) damage. We recently set an in vitro model of BBB, based on a three-cell-type co-culture system, in which rat neurons and astrocytes synergistically induce brain capillary endothelial cells to form a monolayer with permeability properties resembling those of the physiological BBB. Herein we report that the serum from patients with secondary progressive multiple sclerosis (SPMS) has a damaging effect on isolated neurons. This finding suggests that neuronal damaging in MS could be a primary event and not only secondary to myelin damage, as generally assumed. SPMS serum affects the perme…
Extracellular space and electrolyte distribution in cortex and white matter of dog brain in cold induced oedema
1973
24 hours after a circumscribed cold injury of the cortex dog brains were perfused from the lateral ventricle and the frontal subarachnoidal space to the cisterna magna with an artificial CSF containing trace amounts of35S-labelled thiosulphate. Simultaneously the extracellular tracer was administered intravenously. Extracellular fluid volume was estimated and found to be increased from 10 to 15% in the oedematous cortex and from 10 to 27% in the oedematous white matter. The actual size of ECS in oedematous white matter, however, must be larger as indicated by the relative alterations of thiosulphate distribution, tissue water, sodium and chloride. Apparently a small part of the fluid accumu…
KLEIP Deficiency in Mice Causes Progressive Corneal Neovascular Dystrophy
2012
PURPOSE. The BTB-kelch protein KLEIP/KLHL20 is an actin binding protein that regulates cell-cell contact formation and cell migration. The aim of our study was to characterize KLEIP’s function in ocular health and disease in mice. METHODS. KLEIP -/- mice were generated, and corneas were examined histologically and stained for keratin-1, loricrin, keratin-12, keratin-14, CD31, LYVE-1, F4/80, E-cadherin, and Ki67. Corneal abrasions were performed after eyelid opening. RESULTS. Corneas of KLEIP þ/þ and KLEIP -/- mice were indistinguishable at birth. After eyelid opening corneal epithelial hyperplasia started to manifest in KLEIP -/- mice, showing a progressive epithelial metaplasia leading to …