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Linear Density (linear + density)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Monosodium urate monohydrate crystal,induced inflammation in vivo: Quantitative histomorphometric analysis of cellular events

ARTHRITIS & RHEUMATISM, Issue 6 2002
C. Schiltz
Objective To quantify the inflammatory cell response in rat air pouch pseudosynovial membrane during monosodium urate monohydrate (MSU) crystal,induced inflammation. Methods In the rat air-pouch model, we used a computer-assisted histomorphometric method to quantify cell distributions, based on cell linear densities, in histologic sections of membranes from pouches injected with MSU or saline. The volume, white blood cell (WBC) count, and histamine content of the pouch exudates were determined at several time points. Results Injection of 10 mg of MSU crystals into the pouch produced an acute exudate. After peaking at 24 hours, the exudate volume and WBC count decreased spontaneously over the next 3 days, simulating the self-limited course of acute gout. Membrane thickness followed a parallel course. Membrane polymorphonuclear cell (PMN) linear densities were closely correlated with exudate WBC counts, suggesting PMN recruitment from the subintimal synovial membrane. Both monocyte/macrophage and mast cell linear densities increased in the subintimal layer 2 hours after crystal injection (P = 0.038 and P = 0.03, respectively, versus controls), whereas PMN linear densities showed 2 peaks, one at 4 hours and the other 24 hours. The exudate histamine content peaked 6 hours after crystal injection, when mast cell linear densities were minimal in the membranes, suggesting mast cell degranulation. Conclusion An increase in monocyte/macrophage and mast cell densities in the membrane preceded the PMN influx in the pouch membrane and exudate, suggesting that mast cells may be involved in the early phase of MSU crystal,induced inflammation, at least in this rat model. [source]

On the orbital motion of a rotating inner cylinder in annular flow

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 2 2007
Shunxin Feng
Abstract In this paper, numerical calculations have been performed to analyse the influence of the orbital motion of an inner cylinder on annular flow and the forces exerted by the fluid on the inner cylinder when it is rotating eccentrically. The flow considered is fully developed laminar flow driven by axial pressure gradient. It is shown that the drag of the annular flow decreases initially and then increases with the enhancement of orbital motion, when it has the same direction as the inner cylinder rotation. If the eccentricity and rotation speed of the inner cylinder keep unchanged (with respect to the absolute frame of reference), and the orbital motion is strong enough that the azimuthal component (with respect to the orbit of the orbital motion) of the flow-induced force on the inner cylinder goes to zero, the flow drag nearly reaches its minimum value. When only an external torque is imposed to drive the eccentric rotation of the inner cylinder, orbital motion may occur and, in general, has the same direction as the inner cylinder rotation. Under this condition, whether the inner cylinder can have a steady motion state with force equilibrium, and even what type of motion state it can have, is related to the linear density of the inner cylinder. Copyright © 2006 John Wiley & Sons, Ltd. [source]

European Federation of Neurological Societies/Peripheral Nerve Society Guideline on the use of skin biopsy in the diagnosis of small fiber neuropathy.

JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 2 2010
Report of a joint task force of the European Federation of Neurological Societies, the Peripheral Nerve Society
Revision of the guidelines on the use of skin biopsy in the diagnosis of peripheral neuropathy, published in 2005, has become appropriate due to publication of more relevant papers. Most of the new studies focused on small fiber neuropathy (SFN), a subtype of neuropathy for which the diagnosis was first developed through skin biopsy examination. This revision focuses on the use of this technique to diagnose SFN. Task force members searched the Medline database from 2005, the year of the publication of the first EFNS guideline, to June 30th, 2009. All pertinent papers were rated according to the EFNS and PNS guidance. After a consensus meeting, the task force members created a manuscript that was subsequently revised by two experts (JML and JVS) in the field of peripheral neuropathy and clinical neurophysiology, who were not previously involved in the use of skin biopsy. Distal leg skin biopsy with quantification of the linear density of intraepidermal nerve fibers (IENF), using generally agreed upon counting rules, is a reliable and efficient technique to assess the diagnosis of SFN (level A recommendation). Normative reference values are available for bright-field immunohistochemistry (level A recommendation) but not yet for confocal immunofluorescence or the blister technique. The morphometric analysis of IENF density, either performed with bright-field or immunofluorescence microscopy, should always refer to normative values matched for age (level A recommendation). Newly established laboratories should undergo adequate training in a well established skin biopsy laboratory and provide their own stratified age and gender-matched normative values, intra- and interobserver reliability, and interlaboratory agreement. Quality control of the procedure at all levels is mandatory (Good Practice Point). Procedures to quantify subepidermal nerve fibers and autonomic innervated structures, including erector pili muscles, and skin vessels are under development but need to be confirmed by further studies. Sweat gland innervation can be examined using an unbiased stereologic technique recently proposed (level B recommendation). A reduced IENF density is associated with the risk of developing neuropathic pain (level B recommendation), but it does not correlate with its intensity. Serial skin biopsies might be useful for detecting early changes of IENF density, which predict the progression of neuropathy, and to assess degeneration and regeneration of IENF (level C recommendation). However, further studies are warranted to confirm the potential usefulness of skin biopsy with measurement of IENF density as an outcome measure in clinical practice and research. Skin biopsy has not so far been useful for identifying the etiology of SFN. Finally, we emphasize that 3-mm skin biopsy at the ankle is a safe procedure based on the experience of 10 laboratories reporting absence of serious side effects in approximately 35,000 biopsies and a mere 0.19% incidence of non-serious side effects in about 15 years of practice (Good Practice Point). [source]

Influence of yarn texture on the mechanical properties of textile composite castings

POLYMER COMPOSITES, Issue 2 2010
A. Zadhoush
In this research, mechanical properties of textile composite castings used for immobilizing a damaged limb have been studied. For this purpose, a fabric composite was made using a new knitted fabric and textured yarn for the first time. This composite possesses suitable mechanical properties. Mechanical and physical properties such as tensile, bending, and thickness of materials were studied. Results indicate that the use of textured yarns instead of flat yarns increases the amount of resin retainment in fabrics. Furthermore, it decreases tensile modulus and bending modulus of fabrics. Properties of the castings produced were compared with a valid commercial casting. Sample with textured warp and weft, with linear density of 1,500 den of weft, had the best physical and mechanical properties among produced samples. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers [source]

Transgenic neuronal nitric oxide synthase expression induces axotomy-like changes in adult motoneurons

THE JOURNAL OF PHYSIOLOGY, Issue 18 2010
Fernando Montero
Dysregulation of protein expression, function and/or aggregation is a hallmark of a number of neuropathological conditions. Among them, upregulation and/or de novo expression of the neuronal isoform of nitric oxide (NO) synthase (nNOS) commonly occurs in diverse neurodegenerative diseases and in axotomized motoneurons. We used adenoviral (AVV) and lentiviral (LVV) vectors to study the effects of de novo nNOS expression on the functional properties and synaptic array of motoneurons. AVV-nNOS injection into the genioglossus muscle retrogradely transduced neonatal hypoglossal motoneurons (HMNs). Ratiometric real-time NO imaging confirmed that transduced HMNs generated NO gradients in brain parenchyma (space constant: ,12.3 ,m) in response to a glutamatergic stimulus. Unilateral AVV-nNOS microinjection in the hypoglossal nucleus of adult rats induced axotomy-like changes in HMNs. Specifically, we found alterations in axonal conduction properties and the recruitment order of motor units and reductions in responsiveness to synaptic drive and in the linear density of synaptophysin-positive puncta opposed to HMN somata. Functional alterations were fully prevented by chronic treatment with nNOS or soluble guanylyl cyclase inhibitors. Synaptic and functional changes were also completely avoided by prior intranuclear injection of a neuron-specific LVV system for miRNA-mediated nNOS knock-down (LVV-miR-shRNA/nNOS). Furthermore, synaptic and several functional changes evoked by XIIth nerve injury were to a large extent prevented by intranuclear administration of LVV-miR-shRNA/nNOS. We suggest that nNOS up-regulation creates a repulsive NO gradient for synaptic boutons underlying most of the functional impairment undergone by injured motoneurons. This further strengthens the case for nNOS targeting as a plausible strategy for treatment of peripheral neuropaties and neurodegenerative disorders. [source]