Search results for "biophysic"
showing 10 items of 3565 documents
Lumbar mobility in former élite male weight-lifters, soccer players, long-distance runners and shooters
1996
OBJECTIVE: To investigate the long-term effects of different loading conditions in sports and work on lumbar mobility. DESIGN: Factors associated with lumbar mobility were sought by examining sports experience, occupational history, back pain history, anthropometric characteristics, and lumbar magnetic resonance images in 114 former Finnish male élite athletes: 30 soccer players, 29 weight-lifters, 27 long-distance runners, and 28 shooters, aged 45-68 yr. BACKGROUND: Back pain and aging reduce spinal mobility, whereas some sports may increase it. Little is known about the effects of common loading conditions found in work and sports, that do not require extremes of spinal motion on lumbar m…
Clinical support in radiation therapy scenarios: MR brain tumor segmentation using an unsupervised fuzzy C-Means clustering technique
2016
Embryonic and foetal Islet-1 positive cells in human hearts are also positive to c-Kit.
2011
During embryogenesis, the mammalian heart develops from a primitive heart tube originating from two bilateral primary heart fields located in the lateral plate mesoderm. Cells belongings to the pre-cardiac mesoderm will differentiate into early cardiac progenitors, which express early transcription factors which are also common to the Isl-1 positive cardiac progenitor cells isolated from the developing pharyngeal mesoderm and the foetal and post-natal mice hearts. A second population of cardiac progenitor cells positive to c-Kit has been abundantly isolated from adult hearts. Until now, these two populations have been considered two different sets of progenitor cells present in the heart in…
Verification of a commercial implementation of the Macro-Monte-Carlo electron dose calculation algorithm using the virtual accelerator approach.
2009
Abstract In this work, the accuracy of the implementation of the Macro Monte Carlo electron dose calculation algorithm into the radiation therapy treatment planning system Eclipse is evaluated. This implementation – called eMC – uses a particle source based on the Rotterdam Initial Phase-Space model. A three-dimensional comparison of eMC calculated dose to dose distributions resulting from full treatment head simulations with the Monte Carlo code package EGSnrc is performed using the ‘virtual accelerator’ approach. Calculated dose distributions are compared for a homogeneous tissue equivalent phantom and a water phantom with air and bone inhomogeneities. The performance of the eMC algorithm…
Focal elevation of liver microsomal epoxide hydrolase in early preneoplastic stages and its behaviour in the further course of hepatocarcinogenesis.
1981
Abstract Treatment of rats with N-nitrosomorpholine (NNM) for 7 weeks led to a focal increase in liver microsomal epoxide hydrolase (EH) as early as 2 weeks after withdrawal of the carcinogen. This treatment also leads to hyperplastic nodules and liver tumors, but much later. At the same early time point, ATPase activity was decreased in the same islands. Most of these areas already had increased γ-glutamyltranspeptidase activity. The increase in EH at this early time point was more distinct than the decrease in ATPase which has thus far been considered a suitable marker of the earliest stages in hepatocarcinogenesis. The focal increase in EH was also observed in all benign hepatomas, but n…
Proton conductance of human transient receptor potential-vanilloid type-1 expressed in oocytes of Xenopus laevis and in Chinese hamster ovary cells.
2004
Transient receptor potential-vanilloid type-1 (TRPV1) is a ligand-gated cation channel with preference for divalent cations, especially Ca(2+) (sequence of conductances: Ca(2+)Mg(2+)Na(+) approximately/= K(+) approximately/= Cs(+)). In the present study, the two-electrode voltage-clamp technique was used on oocytes of Xenopus laevis expressing TRPV1 to evaluate whether human TRPV1 also conducts protons. In medium devoid of K(+), Na(+), Mg(2+), and Ca(2+), capsaicin 1 microM induced a significant inward current (62% of the current in physiological medium). The effects of capsaicin were abolished in the presence of capsazepine 3 microM. The capsaicin-induced currents in medium devoid of Na(+)…
Automatic scanning of large tissue areas in neurosurgery using optical coherence tomography
2012
Background With its high spatial and temporal resolution, optical coherence tomography (OCT) is an ideal modality for intra-operative imaging. One possible application is to detect tumour invaded tissue in neurosurgery, e.g. during complete resection of glioblastoma. Ideally, the whole resection cavity is scanned. However, OCT is limited to a small field of view (FOV) and scanning perpendicular to the tissue surface. Methods We present a new method to use OCT for scanning of the resection cavity during neurosurgical resection of brain tumours. The main challenges are creating a map of the cavity, scanning perpendicular to the surface and merging the three-dimensional (3D) data for intra-ope…
Histopathology of the Harderian gland of rodents exposed to ELF magnetic fields
1993
Abstract The Harderian gland is a possible magnetosensitive organ. The aim of this study was to look at the possible effects on the Harderian gland of mice after exposure to an artificial magnetic field. Sixty 0F1 three-month old female mice were selected for this study. The mice were exposed continuously to an artificial magnetic field of 1 G (10 −4 T) and 50 Hz during a three-month period. The effects were evaluated histologically. The results show, only in the experimental group, non-reversible histopathological lesions with anaplasic foci in 26% of Harderian glands. These lesions also include in situ development of adenocarcinomas. Confidence intervals applied to the statistical studies…
Biophysics of venous return from the brain from the perspective of the pathophysiology of chronic cerebrospinal venous insufficiency
2011
This article discusses the biophysical aspects of venous outflow from the brain in healthy individuals and in patients with chronic cerebrospinal venous insufficiency. Blood flows out of the brain differently, depending on body position. In the supine position it flows out mainly through internal jugular veins, while in the upright position it uses the vertebral veins. This phenomenon is probably not due to the active regulation of the flow but instead results from the collapse of jugular veins when the head is elevated. Such a collapse is associated with a significant increase in flow resistance, which leads to redirection of the flow towards the vertebral pathway. Theoretical calculations…